Fig 1.
TH staining and locomotor activity.
A (a, b, c): TH immunostaining in SN of wt (n = 4, a) and tg (n = 5, b) mice showed no significant difference at 10 m old. B: Time on the rod in the rotarod test showed no difference between tg (n = 11) and their wt littermates (n = 11) at 10 m old. The quantitative data were expressed as mean±SEM and analyzed by Student’s t-test.
Fig 2.
Expression levels of αSyn and phosphorylated αSyn (ser129) in brains of wt and tg mice at 10 m old.
A, B: Tg mice expressed more αSyn and phosphorylated αSyn (p-αSyn) in frontal cortex than wt mice (n = 3 per group). ** p< 0.01, tg vs wt. The quantitative data were expressed as mean±SEM and analyzed by Student’s t-test. C, D: Compared to wt littermates, tg mice showed much higher αSyn and p-αSyn in different tissues of brain including the striatum, frontal cortex, OB, hippocampus and piriform cortex. ** p<0.01, tg vs wt. The quantitative data were expressed as mean±SEM and analyzed by two-way ANOVA. Str: striatum; cot: frontal cortex; OB, olfactory bulb; hip: hippocampus; pir: piriform cortex.
Fig 3.
Both wt and tg mice spent more time on a block with other mouse’s scent than the block carrying its own scent. 3 m old: wt n = 3, tg n = 3; 6 m old: wt n = 3, tg n = 3; 10 m old: wt n = 3, tg n = 4. * p<0.05, ** p<0.01, time on novel scent vs own scent. ΔΔ p< 0.01, tg vs wt on novel scent. The quantitative data were expressed as mean±SEM and analyzed by two-way ANOVA.
Fig 4.
Odor habituation and discrimination on a non-social scent.
A, B and C: As trials progressed, all mice spent gradually reduced time on contacting with a non-social odor. 3 m old: wt n = 3, tg n = 3; 6 m old: wt n = 4, tg n = 4; 10 m old: wt n = 3, tg n = 4. ** p<0.01, trial-5 (T5) vs trial-1 (T1). No significant difference of contacting time in trial-5 was present between wt and tg mice. D, E and F: At 3 m old, both wt and tg mice spent more time on a novel scent (trial-6) than the familiar scent (trial-5). However, at 6 m and 10 m old, tg mice did not sniff the novel scent (trial-6) more than the familiar scent (trial-5). * p< 0.05, time on novel scent vs familiar scent. ΔΔ p< 0.01, tg vs wt on novel scent. The quantitative data were expressed as mean±SEM and analyzed by two-way ANOVA.
Fig 5.
Tg mice at 10 m old seem to spend slightly more time than age-matched wt mice at all intervals on an odor encountered before, but the statistical analysis showed no significant difference between tg (n = 16) and wt (n = 9) controls. The ratios of trial 2/trial 1 were squared, expressed as mean±SEM and analyzed by two-way ANOVA.
Fig 6.
Performance in the odor detection task.
A: In the buried pellet test (bpt), tg mice at 6 m old showed a longer latency to find the pellet than wt mice, and the time got much longer when they grew up to 10 m old. 3 m old: wt n = 15, tg n = 15; 6 m old: wt n = 15, tg n = 15; 10 m old: wt n = 10, tg n = 17. * p< 0.05, ** p< 0.01, tg vs wt. B: All the animals performed well in the visual pellet test (vpt). No significant difference was found in the visual pellet test between wt and tg mice. 3 m old: wt n = 15, tg n = 15; 6 m old: wt n = 15, tg n = 15; 10 m old: wt n = 10, tg n = 17. The quantitative data were expressed as mean±SEM and analyzed by two-way ANOVA.
Fig 7.
Cholinergic denervation in OB of tg mice.
A and B: ChAT+ cells were decreased in mitral cell layer of OB in tg mice (n = 4) at 10 m old than wt littermates (n = 4). * p<0.05 tg vs wt. Scale bar: 100 μm. Arrows indicate the ChAT+ cells. The quantitative data were expressed as mean±SEM and were analyzed by Student’s t-test. C: AchE activity in OB of tg mice (n = 4 in each age group) declined from 6 m old compared with wt mice (n = 4 in each age group). ** p<0.01, tg vs wt. The quantitative data were expressed as mean±SEM and were analyzed by two-way ANOVA. D: In cerebral cortex, AchE activity did not change between tg (n = 4 in each age group) and wt controls (n = 4 in each age group) at 10 m old. The quantitative data were expressed as mean±SEM and analyzed by two-way ANOVA.
Fig 8.
Increased DAergic neurons and TH level in OB of tg mice.
A and B: TH+ neurons were increased in glomerular layer of OB in tg mice (n = 4) at 10 m old than wt littermates (n = 4). ** p<0.01, tg vs wt. Scale bar: 30 μm. Arrows indicate the TH+ cells. The quantitative data were expressed as mean±SEM and analyzed by Student’s t-test. C and D: Higher TH protein level was found in OB of tg mice (n = 5 in each age group) after 6 m old than wt mice (n = 5 in each age group). * p< 0.05, ** p< 0.01, tg vs wt. The quantitative data were expressed as mean±SEM and analyzed by two-way ANOVA.