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. Author manuscript; available in PMC: 2016 Jan 31.
Published in final edited form as: Stroke. 2014 Dec 18;46(2):485–491. doi: 10.1161/STROKEAHA.114.006372

17β-Estradiol Attenuates Hematoma Expansion through ERα/Sirt1/NF-κB Pathway in Hyperglycemic Intracerebral Hemorrhage Mice

Yun Zheng 1,3,#, Qin Hu 1,#, Anatol Manaenko 1, Yang Zhang 1, Yan Peng 1, Liang Xu 1, Junjia Tang 1, Jiping Tang 1, John H Zhang 1,2,*
PMCID: PMC4308513  NIHMSID: NIHMS643607  PMID: 25523052

Abstract

Background and Purpose

17β-estradiol (E2) has been reported to reduce bleeding and brain injury in experimental intracerebral hemorrhage (ICH) model. However, it is not clear if E2 can prevent early hematoma expansion (HE) induced by hyperglycemia in acute ICH. The aim of this study is to evaluate the effects of E2 on HE and its potential mechanisms in hyperglycemic ICH mice.

Methods

Two hundred, 8-week-old male CD1 mice were used. Intracerebral hemorrhage was performed by collagenase injection. 50% Dextrose (8 ml/kg) was injected intraperitoneally 3 hours after ICH to induce acute HE (normal saline was used as control). The time course of HE was measured 6 hours, 24 hours, and 72 hours after ICH. Two dosages (100 µg/kg and 300 µg/kg) of E2 were administrated 1 hour after ICH intraperitoneally. Neurobehavioral deficits, hemorrhage volume, blood glucose level and blood-brain barrier (BBB) disruption were measured. To study the mechanisms of E2, estrogen receptor α (ERα) inhibitor MPP, Sirt1 siRNA was administered respectively. Protein expression of ERα, Sirt1, and acetylated NF-κB, and activity of MMP-9 were detected.

Results

Hyperglycemia enhanced HE and deteriorated neurological deficits after ICH from 6 hours after ICH. E2 treatment prevented BBB disruption and improved neurological deficits 24 hours and 72 hours after ICH. E2 reduced HE by activating its receptor ERα, decreasing the expression Sirt1, deacelylation of NF-κB and inhibiting the activity of MMP-9. ERα inhibitor MPP and Sirt1 siRNA removed these effects of E2.

Conclusions

E2 treatment prevented hyperglycemia enhanced HE and improved neurological deficits in ICH mice mediated by ERα/Sirt1/NF-κB pathway. E2 may serve as an alternative treatment to decrease early HE after ICH.

Keywords: 17β-Estradiol, Sirt1, MMP-9, Hematoma expansion, intracerebral hemorrhage

Introduction

Spontaneous intracerebral hemorrhage (ICH) is a subtype of stroke featured by hematoma formation within brain parenchyma, which accounts for about 15% of all deaths from stroke and with more than 75% of patients severely disabled or deceased within the first year1. The high mortality and morbidity make ICH a major public health problem, and no effective therapy has yet been established to counteract the consequences of this detrimental subtype of stroke subtype. After ICH the initial hematoma forms and is untreatable. However, approximately 30% of ICH patients continue to bleed and demonstrate significant hematoma expansion (HE), which further aggravates the outcome2. Most HE occurs within 3 hours after the onset of ICH2 and is amenable to treatment3, 4. Because of its strong relationship with poor prognosis and the potential to prevent its development, HE is an appealing therapeutic target after ICH.

Estrogens are steroid compounds that function as the primary sex hormone in females and 17β-estradiol (E2) is the most potent naturally occurring estrogen. In the last two decades, estrogen is one of the most extensively studied neuroprotectants for the treatment of stroke5–8. In experimental ICH model, estrogens have been proven to reduce bleeding and brain injury in rats9–11, while the mechanisms underlie BBB protection of E2 remain poorly explored, and there are no studies to investigate the effects of estrogens on early HE after ICH. Matrix metalloproteinases (MMPs), which is regulated by nuclear factor-kappa B (NF-κB), has been proved to be the culprit for BBB disruption. Recently, E2 has been reported to up-regulate silent information regulator 1 (Sirt1) 12, 13, which can inactivate NF-κB. In the present study, we will investigate whether E2 treatment will prevent the early growth of HE induced by hyperglycemia in ICH mice and explore the potential role of Sirt1/NF-κB in BBB protection.

Materials and Methods

All experiments were approved by the Institutional Animal Care and Use Committee of Loma Linda University.

Animal Model and Experimental Protocol

Two hundred, 8-week-old male CD1 mice (weight 25–35g, Charles River, Wilmington, MA) were used. Intracerebral hemorrhage mouse model was performed by collagenase injection as reported previously14. 50% Dextrose (8 ml/kg) was injected intraperitoneally 3 hours after ICH to induce acute HE (normal saline was used as control). The time course of HE was measured 6 hours, 24 hours, and 72 hours after ICH. Two dosages (100µg/kg and 300µg/kg) of E2 (Sigma-Aldrich) were administrated 1 hour after ICH intraperitoneally. Neurobehavioral deficits, hemorrhage volume and blood glucose were measured. To study the mechanisms of E2, estrogen receptor α (ERα) inhibitor Methyl-piperidino-pyrazole (MPP, Sigma-Aldrich, 100µg/kg), Sirt1 siRNA (OriGene Technologies) was administered respectively. Protein expression of ERα, Sirt1, deacetylated NF-κB, and activity of MMP-9 were detected. The experimental design was included in supplemental figure I.

siRNA Injection

Two different formats of Sirt1 siRNA were applied 48 hours before ICH, in order to enhance the silencing effect. An intracerebroventricular injection (I.C.V) was then performed as previously described14. The Sirt1 siRNA or scramble siRNA mixed with the transfection reagent (OriGene Technologies) (100 pmol/2 µl) was delivered into the ipsilateral ventricle with a Hamilton syringe and administered over 2 minutes. After the needle was removed, the burr hole was sealed with bone wax. The incision was closed with sutures and the mice were allowed to recover.

Neurological Scores

Twenty-four or 72 hours after ICH, the Garcia test was performed by a blinded investigator as previously described with modifications15. The scores given to each of the mice at the completion of the evaluation was the summation of 7 individual test scores (spontaneous activity, symmetry in the movement of four limbs, forepaw outstretching, climbing, body proprioception, response to vibrissae touch, and beam walking). The neurological scoring ranged from 2 (most severe deficit) to 21 (maximum).

Hematoma Volume

Hemoglobin assay was performed as previously described14. The ipsilateral hemisphere was homogenized for 60seconds in a tube with distilled water (total volume 3mL). After centrifuging (12,000 g, 30 minutes), Drabkin's reagent (400 µL, Sigma-Aldrich) was mixed in with a supernatant (100 µL) and allowed to react for 15minutes. The absorbance of the mixture was read with a spectrophotometer (540nm) and the amount of blood in each brain was calculated using a standard curve generated with known blood volumes.

Evan's blue dye extravasation

Disruption of the BBB was analyzed 24 hours after ICH using Evan's blue (EB) dye as reported previously15. The amount of extravasated EB in the brain was determined by spectroflurophotometry with a standard curve. Measurements were conducted at an excitation wavelength of 610 nm.

Immunohistochemistry

Immunofluorescent staining for brain tissue was performed on fixed frozen ultrathin sections as previously described15. Primary antibodies used were ERα (SAB4500810, Sigma-Aldrich), Sirt1 (S5447, Sigma-Aldrich), glial fibrillary acidic protein (GFAP, sc-6170, Santa Cruz Biotechnology) and Von Willebrand factor (vWF, sc-8068, Santa Cruz Biotechnology). Peri-hemorrhagic area of the brain coronal section was imaged by Olympus-BX51.

Western Blot Analysis

Brain samples were collected 24 hours after the ICH. Western blotting was performed as described previously15. Primary antibodies used were: ERα (SAB4500810, Sigma-Aldrich), Sirt1 (S5447, Sigma-Aldrich), acetylated NF-κB (SAB4502616, Sigma-Aldrich) and β-actin (sc-1616, Santa Cruz Biotechnology).

Matrix Metalloproteinase Zymography

The ipsilateral brain cortex was used to analyze MMP-913. Briefly, samples were homogenized and the supernatant was collected. Samples were loaded and separated by 10% Tris-tricine gel with 0.1% gelatin as a substrate. After separation by electrophoresis, the gel was renatured and then incubated with development buffer at 37°C for 24 hours. The gel was stained with 0.5% coomassie blue R-250 for 30 minutes and then destained appropriately. MMP-9 activity was quantified using ImageJ, version 1.32.

Statistical Analysis

The analysis of the data was performed using GraphPad Prism software. Statistical differences between two groups were analyzed using the student`s unpaired, two-tailed t-test. Multiple comparisons (without a rating scale) were statistically analyzed with one-way analysis of variance (ANOVA) followed by the Tukey method. The data are presented as means± SEM. In all statistical analysis, a value of p< 0.05 represents statistical significance.

Results

Hyperglycemia enhanced HE and deteriorated neurobehavioral after ICH

To observe the effects of hyperglycemia on hematoma expansion, we administrated saline or 50% Dextrose (8ml/kg) to the animals 3 hours after ICH, and measured the hemorrhagic volume and neurobehavioral at 6 hours, 24 hours and 72 hours after ICH. There was distinct hematoma formation at the basal ganglia from 6 hours after collagenase injection. In ICH+saline group, the hemorrhagic volume 6 hours, 24 hours and 72 hours were 19.29±1.917 µl, 18.89±1.367 µl, and 13.40±1.056 µl, respectively. Hyperglycemia significantly enhanced HE to 29.70±3.368 µl, 31.87±1.972 µl and 27.40±2.100 µl respectively (Figure 1A and 1B, p<0.05 vs. ICH+saline) and deteriorated neurological deficits. (Figure 1C, p<0.05 vs. ICH+saline). Blood glucose peaked 1 hour after DX injection and returned to baseline within 4 hours, and E2 had no effect on blood glucose level (Figure 1D, p>0.05 vs. ICH+DX).

Figure 1.

Figure 1

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Effects of hyperglycemia on hematoma expansion and neurobehavioral 6 hours, 24 hours and 72 hours after ICH. There was a distinct hematoma formation at the basal ganglia from 6 hours after collagenase injection (A), Hyperglycemia potently enhanced hemorrhagic volume (B) and severely deteriorated the neurological deficits (C) 6 hours, 24 hours and 72 hours after ICH. *p<0.05 vs Sham, &p<0.05 vs. ICH+saline. n=6 for each group.

E2 suppressed HE and improved neurological deficits 24 hours and 72 hours after ICH

A low dosage of E2 showed the tendency to attenuate the HE. A high dosage of E2 significantly decreased hemorrhagic volume (Figure 2A and 2B, p<0.05 vs. ICH+DX+vehicle). This dosage of E2 (300 µg/kg) significantly improved the neurological scores compared with vehicle group 24 hours after ICH (Figure 2C, p<0.05 vs. ICH+DX+vehicle). The beneficial effects of E2 on BBB disruption and neurological deficits last up to 72 hours after ICH (Figure 3, p<0.05 vs. ICH+DX+vehicle).

Figure 2.

Figure 2

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E2 prevented hematoma expansion (A, B) and improved Garcia neuroscores (C) 24 hours after ICH. *p<0.05 vs. sham, & p<0.05 vs. ICH+DX+vehicle. n=6 for each group.

Figure 3.

Figure 3

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E2 prevented hematoma expansion (A, B), improved Garcia neuroscores (C) and preserved the integrity of BBB (D) 72 hours after ICH. *p<0.05 vs. sham, & p<0.05 vs. ICH+DX+vehicle. n=6 for hematoma expansion and Garcia neuroscores in each group; n=5 for Evan’s blue in each group.

ERα inhibitor MPP and Sirt1 siRNA abolished the effects of E2 24 hours after ICH

To investigate the potential mechanisms of E2 in suppressing hematoma expansion, we administrated ERα inhibitor MPP 45 min after ICH and Sirt1 siRNA 48 hours before ICH, respectively with the treatment of a high dosage of E2. MPP significantly increased the hemorrhagic volume from 21.97±1.11 µl to 29.47±1.99 µl (Figure 4A and 4B, p<0.05 vs. ICH+DX+E2), and decreased the neurological scores from 13.17±1.22 to 9.25±0.49 24 hours after ICH (Figure 4C, p<0.05 vs. ICH+DX+E2). Sirt1 siRNA also abolished the effects of E2 by increasing the hemorrhagic volume to 28.25±0.68µl (Figure 4A and 4B, p<0.05 vs. ICH+DX+E2), and decreased the neurological scores from 13.17±1.22 to 9.75±0.62 (Figure 4C, p<0.05 vs. ICH+DX+E2). These data suggested that E2 ameliorated HE dependent on its receptor ERα and Sirt1.

Figure 4.

Figure 4

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ERα inhibitor MPP and Sirt1 siRNA removed the effects of E2 on hematoma expansion (A, B) and Garcia neuroscores (C) 24 hours after ICH. *p<0.05 vs. sham, & p<0.05 vs. ICH+DX+vehicle, # p<0.05 vs. ICH+DX+E2. n=6 for each group.

E2 ameliorated HE by inhibiting the activity of MMP-9 through ERα/Sirt1/NF-κB pathway

Double fluorescence immunostaining showed the expression of ERα and Sirt1 were strong in astrocytes and endothelial cells in sham animals and decreased after ICH (Figure 5). Western blots showed that after ICH, there was a dramatic loss of ERα in ipsilateral brain tissue (Figure 6A, p<0.05 vs. Sham), and administration of E2 significantly up-regulated the expression of ER-α (Figure 6A, p<0.05 vs. ICH+DX+vehicle), while ERα inhibitor MPP didn’t affect the expression of ERα significantly (Figure 6A, p>0.05 vs. ICH+DX+E2). The expression of Sirt1 decreased after ICH (Figure 6B, p<0.05 vs. Sham) and increased by E2 24 hours after ICH (Figure 6B, p<0.05 vs. ICH+DX+vehicle). Sirt1 siRNA strongly knocked down the expression of Sirt1 in both Sham and ICH mice compared with scramble siRNA (Supplement figure II). MPP and Sirt1 siRNA abrogated the results of E2 and decreased the expression of Sirt1 (Figure 6B, p<0.05 vs. ICH+DX+E2). ICH increased the acetylation of NF-κB (Figure 6C, p<0.05 vs. Sham), which was decreased by E2 administration (Figure 6C, p<0.05 vs. ICH+DX+vehicle). Administration of MPP or Sirt1 siRNA increased the acetylated NF-κB in E2 treated animals (Figure 6C, p<0.05 vs. ICH+DX+E2).

Figure 5.

Figure 5

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Representative immunostaining of ERα and Sirt1 in astrocytes and endothelial cells in Sham and ICH animals 24 hours after surgery.

Figure 6.

Figure 6

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E2 reduced hematoma expansion by inhibiting the activity of MMP-9 through ERα/Sirt1/NF-κB pathway. Western blots showed E2 treatment increased the level of ERα (A) and Sirt1 (B), decreased the deacetylation of NF-Κb (C) and activity of MMP-9 (D). ERα inhibitor MPP and Sirt1 siRNA reversed these effects of E2. *p<0.05 vs. sham, & p<0.05 vs. ICH+DX+vehicle, # p<0.05 vs. ICH+DX+E2. n=6 for each group.

The activity of MMP-9 in ICH+DX+vehicle group was intensely increased 24 hours after ICH (Figure 6D, p<0.05 vs. Sham), and was significantly decreased by E2 (Figure 6D, p<0.05 vs. ICH+DX+vehicle). ER-α inhibitor MPP and Sirt1 siRNA abolished the effects of E2 on the activity of MMP-9 (Figure 6D, p<0.05 vs. ICH+DX+E2). The activity of MMP-2 didn’t show great changes in all groups. The results suggested that E2 inhibited the activity of MMP-9 through ERα/Sirt1/NF-κB pathway in ICH mice.

Discussion

Hematoma volume is a major factor of both mortality and poor outcome after ICH. Early HE aggravates initial outcomes and increase mortality. Early HE is, however treatable, and restriction of HE is a promising therapeutic approach. In this study, our goals were to test firstly whether hyperglycemia enhanced early HE in ICH model, secondly whether E2 ameliorated early HE and improved neurobehavioral performance, and thirdly investigated the mechanisms of E2 on blood-brain barrier (BBB) protection. We found out that hyperglycemia can enlarge HE and deteriorate neurological deficits as early as 3 hours after dextrose injection in ICH mice. Administration of E2 significantly decreased the hemorrhagic volume, and improved the neurological deficits both 24 hours and 72 hours after ICH. E2 suppressed the activity of MMP-9 through ERα/Sirt1/NF-κB signaling pathway and inhibition of ERα/Sirt1 abolished the effect of E2. These observations indicated that E2 might serve as an alternative therapeutic strategy to prevent early HE in ICH patients by protecting BBB.

In clinic, hyperglycemia is more common in patients with preexisting diabetes but is also present in a significant proportion of non-diabetic patients. About 60% ICH patients might develop hyperglycemia even in the absence of a previous history of diabetes16, which is probably a response to the stress and severity of ICH. Hyperglycemia is strictly associated with greater HE and worse clinical outcomes after ICH16–20. The deleterious effects of hyperglycemia are attributed to its secondary effects of acidosis, increased free radical formation, and release of inflammatory cytokines, which accelerated the degradation of BBB components and impaired the integrity of adjacent vessels surrounding the initial bleeding site21–23. In streptozotocin-induced diabetic rats and mice, hyperglycemia results in greater HE after ICH20, 24. In the present study, we injected dextrose 3 hours after ICH to mimic hyperglycemia on hospital admission. We found that a greater macroscopic bleeding area was observed around the injection site, and more bleeding volume was confirmed in the hyperglycemic mice from 3 hours after dextrose injection when compared to saline controls. Our findings demonstrated to the first time that hyperglycemia in the acute setting of ICH significantly enhanced early HE and deteriorated neurological outcome. Liu et al. in their excellent study demonstrated that hyperosmolality caused by hyperglycemia let to a hematoma expansion in “autologous blood” model of ICH via activation of kallikrein/platelet signaling pathway24. Our findings show that 50% mannitol did not significantly affect the hematoma expansion (supplement figure III). Hematoma expansion in Liu’s publication was specified as hematoma area in the subarachnoid space. The hematoma volume was not measured by the authors. We, on the contrary, investigated effect of dextrose on the hematoma volume, without examination of the hematoma location. We believe that, due to different scientific targets, there are no contradictions in these two studies.

Even though the precise mechanism of early HE during the acute phase of ICH is poorly understood, it is partly preventable. Inflammatory cascade activation and matrix metalloproteinases (MMPs) overexpression have been claimed to be the major perpetrators in BBB disruption and HE formation after ICH25. Recently, emerging evidence from basic research suggests that estrogens showed potency and efficacy on BBB protection9, 26–28, which might contribute to preventing HE formation in ICH. After brain injury, estrogen exposure ameliorated BBB disruption induced by transient focal cerebral ischemia through inhibition of MMP-2 and MMP-9 activation2,9. In female rats, endogenous estrogen reduced brain edema and improved neurological deficits after ICH when compared with male rats. In collagenase-induced ICH rats estrogen treatment significantly reduced bleeding and lesion volume9. In agreement with this, we observed activation of MMP-9 and HE in hyperglycemic ICH mice, and E2 dramatically suppressed the activity of MMP-9 and reduced early HE. These results justified that early HE is a potential therapeutic target in the acute phase of ICH and E2 treatment may be an accessible and effective strategy to restrict HE and improve neurological functions in clinic.

Next we addressed the role of ERα in HE suppression of E2 after ICH. There are two receptor isoforms of E2, ERα and ERβ; both of which are members of the nuclear receptor transcription factor superfamily. Deficiency of ERα but not of ERβ abolished the protective effect of E2 in ovariectomized mice subjected to focal cerebral ischemia30. Additional studies confirmed that in animals subjected to SAH, there was a significant change in protein expression of ERα but not ERβ in dentate gyrus, and E2 reversed SAH down-regulated ERα and phospho-Akt expression via an ERα -dependent mechanism31. The results of these studies demonstrated that ERα, and not ERβ, was the critical responsible for estrogen-mediated neuroprotection in the rodent cerebral cortex. Furthermore, Vegeto et al., revealed that ERα mediated anti-inflammatory activity of E2 in brain through inhibiting the expression of MMP-932. In transient cerebral ischemia, E2 has been proved attenuated BBB disruption by suppressing the activity of MMP-2 and MMP-929. In our experiment, we observed a decreased expression of ERα and activation of MMP-9 in hemorrhagic hemisphere, which is in agreement with the previous studies. Administration of E2 and ERα inhibitor MPP didn’t affect the level of ERα; while MPP abolished the beneficial effects of E2 on BBB broken. Our data demonstrated that the protective role of E2 on BBB is partially mediated by inhibiting the activity of MMP-9 through ERα in ICH rats.

How does E2/ERα signaling regulate MMP-9? ERα is a member of the nuclear receptors and once ERα is activated, ERα may interact with specific transcriptional co-regulators to modulate gene expression and mediate the effects of E2. The role of sirtuins in the regulation of estrogen receptor signaling has emerged over the years. Sirtuins are a family of highly conserved protein deacetylases that have extensively implicated energy metabolism, stress response and cell/tissue survival. Silent information regulator 1 (Sirt1) is the best characterized family member, resides mainly in the nucleus and deacetylases numerous transcription factors, including p53, nuclear factor-kappaB (NF-κB), forkhead box O (FOXO) and so on. Exciting researches have shown that in a rat model of post-menopausal metabolic syndrome, E2 restored the protein expression of Sirt1 and alleviated endothelial dysfunction12. E2 treatment also has been reported to result in an up-regulation of Sirt1 in old mice13 and in Hela cells33. The studies of Elangovan showed that ERα bound to p53 promoter and suppresses its expression and that the process is obligatorily dependent on Sirt1 in breast cancer cells. In the present study, E2 treatment promoted deacetylation of NF-κB and inactivated its transcription of MMP-9. Sirt1 knockdown abolished this effect, indicating that Sirt1 is necessary for the ability of E2/ERα signaling to suppress MMP-9 and attenuate HE in hyperglycemic ICH rats.

In conclusion, we demonstrated that hyperglycemia enhanced early HE in acute setting of ICH, and administration of E2 prevented the development of HE and improved neurological deficits in ICH mice. E2 preserved the integrity of BBB by suppressing the activity of MMP-9, which is dependent on ERα/Sirt1/NF-κB pathway. Our results suggested that E2 might be a promising approach to restrict early HE after ICH.

Supplementary Material

supplemental material

Acknowledgments

Sources of Funding

This study was supported partially by a grant from NIH NS078755, NS081740, and NS082124 to JHZ.

Footnotes

Disclosures

None.

References

  • 1.Qureshi AI, Mendelow AD, Hanley DF. Intracerebral haemorrhage. Lancet. 2009;373:1632–1644. doi: 10.1016/S0140-6736(09)60371-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 2.Brott T, Broderick J, Kothari R, Barsan W, Tomsick T, Sauerbeck L, et al. Early hemorrhage growth in patients with intracerebral hemorrhage. Stroke. 1997;28:1–5. doi: 10.1161/01.str.28.1.1. [DOI] [PubMed] [Google Scholar]
  • 3.Mayer SA, Brun NC, Begtrup K, Broderick J, Davis S, Diringer MN, et al. Efficacy and safety of recombinant activated factor vii for acute intracerebral hemorrhage. N Engl J Med. 2008;358:2127–2137. doi: 10.1056/NEJMoa0707534. [DOI] [PubMed] [Google Scholar]
  • 4.Anderson CS, Huang Y, Wang JG, Arima H, Neal B, Peng B, et al. Intensive blood pressure reduction in acute cerebral haemorrhage trial (interact): A randomised pilot trial. Lancet Neurol. 2008;7:391–399. doi: 10.1016/S1474-4422(08)70069-3. [DOI] [PubMed] [Google Scholar]
  • 5.Carwile E, Wagner AK, Crago E, Alexander SA. Estrogen and stroke: A review of the current literature. J Neurosci Nurs. 2009;41:18–25. quiz 26-17. [PubMed] [Google Scholar]
  • 6.Dubal DB, Kashon ML, Pettigrew LC, Ren JM, Finklestein SP, Rau SW, et al. Estradiol protects against ischemic injury. J Cereb Blood Flow Metab. 1998;18:1253–1258. doi: 10.1097/00004647-199811000-00012. [DOI] [PubMed] [Google Scholar]
  • 7.Yang SH, He Z, Wu SS, He YJ, Cutright J, Millard WJ, et al. 17-beta estradiol can reduce secondary ischemic damage and mortality of subarachnoid hemorrhage. J Cereb Blood Flow Metab. 2001;21:174–181. doi: 10.1097/00004647-200102000-00009. [DOI] [PubMed] [Google Scholar]
  • 8.Sudo S, Wen TC, Desaki J, Matsuda S, Tanaka J, Arai T, et al. Beta-estradiol protects hippocampal ca1 neurons against transient forebrain ischemia in gerbil. Neurosci Res. 1997;29:345–354. doi: 10.1016/s0168-0102(97)00106-5. [DOI] [PubMed] [Google Scholar]
  • 9.Auriat A, Plahta WC, McGie SC, Yan R, Colbourne F. 17beta-estradiol pretreatment reduces bleeding and brain injury after intracerebral hemorrhagic stroke in male rats. J Cereb Blood Flow Metab. 2005;25:247–256. doi: 10.1038/sj.jcbfm.9600026. [DOI] [PubMed] [Google Scholar]
  • 10.Nakamura T, Hua Y, Keep RF, Park JW, Xi G, Hoff JT. Estrogen therapy for experimental intracerebral hemorrhage in rats. J Neurosurg. 2005;103:97–103. doi: 10.3171/jns.2005.103.1.0097. [DOI] [PubMed] [Google Scholar]
  • 11.Nakamura T, Xi G, Keep RF, Wang M, Nagao S, Hoff JT, et al. Effects of endogenous and exogenous estrogen on intracerebral hemorrhage-induced brain damage in rats. Acta Neurochir Suppl. 2006;96:218–221. doi: 10.1007/3-211-30714-1_47. [DOI] [PubMed] [Google Scholar]
  • 12.Bendale DS, Karpe PA, Chhabra R, Shete SP, Shah H, Tikoo K. 17-beta oestradiol prevents cardiovascular dysfunction in post-menopausal metabolic syndrome by affecting sirt1/ampk/h3 acetylation. Br J Pharmacol. 2013;170:779–795. doi: 10.1111/bph.12290. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 13.Elbaz A, Rivas D, Duque G. Effect of estrogens on bone marrow adipogenesis and sirt1 in aging c57bl/6j mice. Biogerontology. 2009;10:747–755. doi: 10.1007/s10522-009-9221-7. [DOI] [PubMed] [Google Scholar]
  • 14.Ma Q, Chen S, Hu Q, Feng H, Zhang JH, Tang J. Nlrp3 inflammasome contributes to inflammation after intracerebral hemorrhage. Ann Neurol. 2014;75:209–219. doi: 10.1002/ana.24070. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 15.Hu Q, Chen C, Yan J, Yang X, Shi X, Zhao J, et al. Therapeutic application of gene silencing mmp-9 in a middle cerebral artery occlusion-induced focal ischemia rat model. Exp Neurol. 2009;216:35–46. doi: 10.1016/j.expneurol.2008.11.007. [DOI] [PubMed] [Google Scholar]
  • 16.Godoy DA, Pinero GR, Svampa S, Papa F, Di Napoli M. Hyperglycemia and short-term outcome in patients with spontaneous intracerebral hemorrhage. Neurocrit Care. 2008;9:217–229. doi: 10.1007/s12028-008-9063-1. [DOI] [PubMed] [Google Scholar]
  • 17.Lee SH, Kim BJ, Bae HJ, Lee JS, Lee J, Park BJ, et al. Effects of glucose level on early and long-term mortality after intracerebral haemorrhage: The acute brain bleeding analysis study. Diabetologia. 2010;53:429–434. doi: 10.1007/s00125-009-1617-z. [DOI] [PubMed] [Google Scholar]
  • 18.Kimura K, Iguchi Y, Inoue T, Shibazaki K, Matsumoto N, Kobayashi K, et al. Hyperglycemia independently increases the risk of early death in acute spontaneous intracerebral hemorrhage. J Neurol Sci. 2007;255:90–94. doi: 10.1016/j.jns.2007.02.005. [DOI] [PubMed] [Google Scholar]
  • 19.Stead LG, Jain A, Bellolio MF, Odufuye A, Gilmore RM, Rabinstein A, et al. Emergency department hyperglycemia as a predictor of early mortality and worse functional outcome after intracerebral hemorrhage. Neurocrit Care. 2010;13:67–74. doi: 10.1007/s12028-010-9355-0. [DOI] [PubMed] [Google Scholar]
  • 20.Song EC, Chu K, Jeong SW, Jung KH, Kim SH, Kim M, et al. Hyperglycemia exacerbates brain edema and perihematomal cell death after intracerebral hemorrhage. Stroke. 2003;34:2215–2220. doi: 10.1161/01.STR.0000088060.83709.2C. [DOI] [PubMed] [Google Scholar]
  • 21.Allen CL, Bayraktutan U. Antioxidants attenuate hyperglycaemia-mediated brain endothelial cell dysfunction and blood-brain barrier hyperpermeability. Diabetes Obes Metab. 2009;11:480–490. doi: 10.1111/j.1463-1326.2008.00987.x. [DOI] [PubMed] [Google Scholar]
  • 22.Kamada H, Yu F, Nito C, Chan PH. Influence of hyperglycemia on oxidative stress and matrix metalloproteinase-9 activation after focal cerebral ischemia/reperfusion in rats: Relation to blood-brain barrier dysfunction. Stroke. 2007;38:1044–1049. doi: 10.1161/01.STR.0000258041.75739.cb. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 23.Esposito K, Nappo F, Marfella R, Giugliano G, Giugliano F, Ciotola M, et al. Inflammatory cytokine concentrations are acutely increased by hyperglycemia in humans: Role of oxidative stress. Circulation. 2002;106:2067–2072. doi: 10.1161/01.cir.0000034509.14906.ae. [DOI] [PubMed] [Google Scholar]
  • 24.Liu J, Gao BB, Clermont AC, Blair P, Chilcote TJ, Sinha S, et al. Hyperglycemia-induced cerebral hematoma expansion is mediated by plasma kallikrein. Nat Med. 2011;17:206–210. doi: 10.1038/nm.2295. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 25.Li Y, Ogle ME, Wallace GCt, Lu ZY, Yu SP, Wei L. Erythropoietin attenuates intracerebral hemorrhage by diminishing matrix metalloproteinases and maintaining blood-brain barrier integrity in mice. Acta Neurochir Suppl. 2008;105:105–112. doi: 10.1007/978-3-211-09469-3_22. [DOI] [PubMed] [Google Scholar]
  • 26.Shin JA, Yang SJ, Jeong SI, Park HJ, Choi YH, Park EM. Activation of estrogen receptor beta reduces blood-brain barrier breakdown following ischemic injury. Neuroscience. 2013;235:165–173. doi: 10.1016/j.neuroscience.2013.01.031. [DOI] [PubMed] [Google Scholar]
  • 27.Sandoval KE, Witt KA. Age and 17beta-estradiol effects on blood-brain barrier tight junction and estrogen receptor proteins in ovariectomized rats. Microvasc Res. 2011;81:198–205. doi: 10.1016/j.mvr.2010.12.007. [DOI] [PubMed] [Google Scholar]
  • 28.Rutkowsky JM, Wallace BK, Wise PM, O'Donnell ME. Effects of estradiol on ischemic factor-induced astrocyte swelling and aqp4 protein abundance. American journal of physiology. Am J Physiol Cell Physiol. 2011;301:C204–C212. doi: 10.1152/ajpcell.00399.2010. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 29.Liu R, Wen Y, Perez E, Wang X, Day AL, Simpkins JW, et al. 17beta-estradiol attenuates blood-brain barrier disruption induced by cerebral ischemia-reperfusion injury in female rats. Brain Res. 2005;1060:55–61. doi: 10.1016/j.brainres.2005.08.048. [DOI] [PubMed] [Google Scholar]
  • 30.Dubal DB, Zhu H, Yu J, Rau SW, Shughrue PJ, Merchenthaler I, et al. Estrogen receptor alpha, not beta, is a critical link in estradiol-mediated protection against brain injury. Proc Natl Acad Sci U S A. 2001;98:1952–1957. doi: 10.1073/pnas.041483198. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 31.Kao CH, Chang CZ, Su YF, Tsai YJ, Chang KP, Lin TK, et al. 17beta-estradiol attenuates secondary injury through activation of akt signaling via estrogen receptor alpha in rat brain following subarachnoid hemorrhage. J Surg Res. 2013;183:e23–e30. doi: 10.1016/j.jss.2013.01.033. [DOI] [PubMed] [Google Scholar]
  • 32.Vegeto E, Belcredito S, Etteri S, Ghisletti S, Brusadelli A, Meda C, et al. Estrogen receptor-alpha mediates the brain antiinflammatory activity of estradiol. Proc Natl Acad Sci U S A. 2003;100:9614–9619. doi: 10.1073/pnas.1531957100. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 33.Han L, Wang P, Zhao G, Wang H, Wang M, Chen J, et al. Upregulation of sirt1 by 17beta-estradiol depends on ubiquitin-proteasome degradation of ppar-gamma mediated by nedd4-1. Protein Cell. 2013;4:310–321. doi: 10.1007/s13238-013-2124-z. [DOI] [PMC free article] [PubMed] [Google Scholar]

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