Abstract
Objective
To investigate effects of KATP opener on the expressions of caspase-12 mRNA and protein, and to explore the role of endoplasmic reticulum (ER) stress pathway in the mechanism of KATP opener protecting against neuronal apoptosis after cerebral ischemia-reperfusion.
Methods
Two hundred rats were randomly divided into four groups: sham operation group, ischemia-reperfusion group, KATP opener group, and KATP blocker group. The middle cerebral artery occlusion (MCAO) model was established by intraluminal suture occlusion method; neuronal apoptosis was detected by TUNEL staining. The mRNA and protein expressions of caspase-12 were detected by semi-quantitative RT-PCR and immunohistochemical staining, respectively.
Results
In ischemia-reperfusion group, KATP opener group and KATP blocker group, the number of apoptotic cells and the mRNA and protein expressions of caspase-12 gradually increased following cerebral reperfusion, and reached the peak at 24 h. In KATP opener group, The number of apoptotic cells was significantly less than that in ischemia-reperfusion group and KATP blocker group at 12 h, 24 h, 48 h and 72 h (P < 0.05 or P < 0.01); while the mRNA and protein levels of caspase-12 were significantly less than those in ischemia-reperfusion group and KATP blocker group at all times (P < 0.05 or P < 0.01). There were no differences between the ischemia-reperfusion group and KATP blocker group at each time (P > 0.05).
Conclusion
KATP opener may protect neurons from apoptosis following the cerebral ischemia-reperfusion by inhibiting ER stress pathway.
Keywords: ATP sensitive potassium channel, cerebral ischemia, apoptosis, endoplasmic reticulum, caspase-12
摘要
目的
观察 ATP 敏感性钾通道 (KATP) 开放剂对大鼠脑缺血再灌注后 caspase-12 mRNA 和蛋白表达的影响, 探讨内质网信号通路是否参与了 KATP 开放剂对脑缺血后神经元凋亡的抑制机制。
方法
200 只 Wistar 雄性大鼠随机分为假手术组, 缺血再灌注组, 开放剂组及阻断剂组。 应用线栓法制备大鼠大脑中动脉缺血再灌注模型, 分别应用免疫组化染色、 RT-PCR 技术检测脑缺血再灌注后各组 caspase-12 蛋白及 mRNA 的表达。
结果
在缺血再灌注组, 开放剂组及阻断剂组, 随着缺血再灌注时间的延长, caspase-12 mRNA 及蛋白的表达逐渐增高, 在缺血再灌注后 24 h 达高峰。 开放剂组 caspase-12 mRNA 及蛋白表达在各时间点均显著少于缺血再灌注组及阻断剂组 (P < 0.05 或 P < 0.01)。 阻断剂组各时间点与缺血再灌注组相比均无显著性差异 (P > 0.05)。
结论
KATP 开放剂可能通过抑制内质网信号通路, 减少神经元凋亡, 降低脑缺血再灌注损伤。
关键词: ATP 敏感性钾通道开放剂, 脑缺血, 凋亡, 内质网, Caspase-12
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