Table 2. Nicotine treatment for 6 months did not alter histological parameters in SN and striatum.
Thy1-aSyn mice showed increased α-synuclein levels overall in SN (SNc, SN pars compacta; SNr, SN pars reticulata) compared to Wt mice treated with vehicle; and nicotine treatment did not alter these levels. The percentage area occupied by the proteinase K-resistant aggregates in SN subregions of Thy1-aSyn mice was not altered by nicotine treatment for 6 months. Other parameters show μm2 / section. TH immunofluorescence was not altered in Thy1-aSyn mice compared to Wt mice treated with vehicle in both SN and striatum. Nicotine treatment for 6 months did not change nigral or striatal tyrosine TH immunofluorescence compared to vehicle-treated Thy1-aSyn mice. Thy1-aSyn mice showed no change in striatal synaptophysin or MAP2 (microtubule-associated protein 2) immunofluorescence compared to vehicle-treated Wt mice. Nicotine treatment for 6 months did not alter striatal synaptophysin or MAP2 immunofluorescence at several levels (rostral, medial and caudal) compared to vehicle-treated Thy1-aSyn mice. Data are presented as the mean ± SEM; Wt-vehicle (n=8-10), Thy1-aSyn-vehicle (n=8-10), Thy1-aSyn-0.4 mg/kg/h (n=8-10), Thy1-aSyn-2.0 mg/kg/h (n=8-10); repeated measures ANOVA followed by a post hoc Bonferroni t test. *p<0.05, compared to Wt vehicle group within the brain sub-region. ^p<0.05, Thy1-aSyn-0.4 mg/kg/h group vs Thy1-aSyn-2.0 mg/kg/h group within the brain sub-region. β = Thy1-aSyn-nicotine-2.0 mg/kg/h mice were euthanized at 6 months of age (see Methods) and their brains were processed for histology.
| Immunohistological measurements | Genotype | Nicotine mg/kg/h | Brain Region (with sub-regions) | |||
|---|---|---|---|---|---|---|
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SN
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| SNc | SNr | |||||
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| α-synuclein (immunofluorescence) | Wt | 0 | 18900 ± 2100 | 29900 ± 2400 | ||
| Thy1-aSyn | 0 | 30100 ± 2400* | 35000 ± 2600 | |||
| Thy1-aSyn | 0.4 | 28700 ± 3200* | 33400 ± 3500 | |||
| Thy1-aSyn | 2.0 β | 26900 ± 2700* | 31500 ± 2400 | |||
|
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| α-synuclein aggregates (proteinase K-resistant) | Dorsolateral | Dorsomedial | Ventrolateral | Ventromedia | ||
|
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| Thy1-aSyn | 0 | 1.16±0.10 | 0.99±0.07 | 1.11±0.10 | 1.18±0.08 | |
| Thy1-aSyn | 0.4 | 1.14±0.05 | 1.03±0.07 | 1.18±0.08 | 1.17±0.07 | |
| Thy1-aSyn | 2.0 β | 1.21±0.08 | 1.06±0.04 | 1.35±0.09 | 1.20±0.07 | |
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| TH (immunofluorescence) | SNc | SNr | ||||
|
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| Wt | 0 | 13400 ± 880 | 7570 ± 450 | |||
| Thy1-aSyn | 0 | 13500 ± 610 | 7380 ± 370 | |||
| Thy1-aSyn | 0.4 | 15300 ±1300 | 7570 ± 550 | |||
| Thy1-aSyn | 2.0 β | 12700 ± 840^ | 6870 ± 400 | |||
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|
striatum
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| Rostral | Medial | Caudal | ||||
|
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| TH (immunofluorescence) | Wt | 0 | 23000 ± 1200 | 19270 ± 1310 | 19100 ± 930 | |
| Thy1-aSyn | 0 | 22400 ± 1400 | 18090 ± 1140 | 17110 ± 930 | ||
| Thy1-aSyn | 0.4 | 23800 ± 1100 | 19740 ± 1360 | 19100 ±1100 | ||
| Thy1-aSyn | 2.0 β | 20200 ± 1500^ | 17140 ± 890 | 16400 ± 490 | ||
|
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| Synaptophysin (immunofluorescence) | Wt | 0 | 47200 ± 1700 | 33200 ± 1500 | 33400 ± 1900 | |
| Thy1-aSyn | 0 | 47300 ± 2200 | 30700 ± 1700 | 29700 ± 1300 | ||
| Thy1-aSyn | 0.4 | 46100 ±1500 | 31200 ± 1500 | 31600 ± 1200 | ||
| Thy1-aSyn | 2.0 β | 52700 ±1800 | 34300 ± 1700 | 33200 ± 1600 | ||
|
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| MAP2 (immunofluorescence) | Wt | 0 | 33600 ± 1700 | 29500 ± 2500 | 30100 ± 2700 | |
| Thy1-aSyn | 0 | 38200 ± 2000 | 30200 ± 2100 | 30600 ± 1700 | ||
| Thy1-aSyn | 0.4 | 33300 ± 2100 | 27900 ± 1000 | 28900 ± 1000 | ||
| Thy1-aSyn | 2.0 β | 34800 ± 2200 | 30700 ± 2500 | 30600 ± 2000 | ||