ABSTRACT
Objective:To explore the effect and molecular mechanism of capsaicin receptor(TRPV1) on neuronal autophagy and depression-like behavior in mice.Methods:Using the method of random number table, 87 C57 male mice were divided into Sham operation group (Sham group), cerebral ischemia/reperfusion group (I/R group) and capsazepine(CPZ) preconditioning cerebral ischemia/reperfusion group (I/R+ CPZ group), with 28 mice in each group due to 3 incompatible.Mice in the I/R group were subjected to right middle cerebral artery occlusion (MCAO) to establish a cerebral ischemia-reperfusion model.Mice in the I/R+ CPZ group were injected with CPZ in the lateral ventricle prior to moulding.Mice in the Sham group had only wire plugs inserted and no arterial embolization was performed.The mNSS score was used to evaluate the degree of neurological deficits.The depression-like behaviour of mice was detected by the tail suspension test and forced swimming test.The infarct volume was observed by TTC staining.The pathological changes in the amygdala were observed by HE staining, and the expression of Beclin-1, LC3, p62 and p-PI3K, p-AKT and p-mTOR proteins were detected by Western blot.Statistical analysis was performed using SPSS 23.0 software.The t-test was used for comparison between two groups and one-way ANOVA was used for comparison of multiple group. Results:The neurological deficit score in I/R+ CPZ group (9.77±2.32) was significantly lower than that in I/R group (12.85±2.73) ( t=3.10, P<0.01). Compared with I/R group, the tail suspension immobility time of I/R+ CPZ Group ((93.28±50.69)s, (143.80±35.61) s; t=2.94, P<0.01) and the forced swimming immobility time ((139.50±13.33)s, (175.30±19.78)s; t=2.94, P<0.01) were significantly reduced.The results of TTC staining showed that the cerebral infarct volume in I/R+ CPZ group was significantly lower than that in I/R group ((19.30±5.19)%, (33.60±3.90)%; t=5.40, P<0.01). HE staining showed that the number of cells in the amygdala region of mice in the I/R+ CPZ group increased compared with that in the I/R group, with tighter arrangement and reduced deep staining of nuclear fixation.Western blot showed that compared with I/R group, the expression levels of autophagy related proteins Beclin-1( t=2.94, P<0.05) and LC3 ( t=3.16, P<0.05) in amygdala of I/R+ CPZ group were down-regulated, while the expression levels of p62( t=3.60, P<0.05), p-PI3K ( t=7.79, P<0.01), p-AKT ( t=4.15, P<0.01) and p-mTOR ( t=6.15, P<0.01) were up-regulated. Conclusion:Cerebral ischemia/reperfusion activates neuronal autophagy, and CPZ may regulate the PI3K-AKT-mTOR pathway, thus inhibits excessive activation of autophagy, thereby acting as a neuroprotective agent and improving post-stroke depression-like behaviour.
ABSTRACT
Objective To investigate the effects of 14-3-3 phosphorylation (p-14-3-3) induced by C-Jun N-termi-nal kinase (JNK) on ischemic brain injury in rats. Methods Twenty rats were divided into 4 groups:sham operation group, ischemia-reperfusion group, SP600125 group and solvent control group. The rat model of cerebral ischemia was established. The p-14-3-3, the binding of 14-3-3 and Bax and the protein expression of Bax in cytoplasm and mitochondria in hippo-campal CA1 region were detected by immunoprecipitation (IP) and immunoblotting 12-hour after ischemia-reperfusion in four groups. Results Compared with the sham operation group, protein expression levels of p-14-3-3 in cytoplasm and Bax in mitochondria were significantly increased, the binding of 14-3-3 and Bax was significantly decreased in ischemia-re-perfusion group, solvent control group and SP600125 group. The protein expressions of p-14-3-3 and Bax were significantly lower in SP600125 group than those of ischemia-reperfusion group and solvent control group. The binding of 14-3-3 and Bax was significantly higher in SP600125 group than that of ischemia-reperfusion group and solvent control group (P <0.05). Conclusion 14-3-3 phosphorylation induced by JNK plays important effects on ischemic brain injury in rats.
ABSTRACT
Objective To explore the effects of mangiterin on behaviors and brain-derived neurotrophic factor(BDNF) of hippocampus in chronic stress depression mice.Methods 60 male mice were randomly divided into normol control group,model group,fluoxetin control group and mangiterin groups (low,medium and high dose),10 mice in each group.All mice except normal control group were singly housed and subjected to chronic stress-induced depression model for 21 consecutive days.The behaviors of mice were detected by open-field test and tail-suspension test.The expression of BDNF in the hippocampus were assessed using western blot.Results Compared with the normal group,mice exposed chronic stress showed decreased body weight((5.33 ±1.20) g),crossing lines (102 ± 18) and distances ((3425 ± 112) mm) notably decreased in open-field behavior test.The duration of immobility during tail-suspension was increased significantly.BDNF expression in the hippocampus(0.45 ± 0.03) was downregulated significantly(P＜ 0.01),while it was upregulated in the groups of mangiterin(P ＜ 0.01).Mangiterin group in high dose had the similar effects to fluoxetin group(P ＞ 0.05).Conclusion Mangiterin can ameliorate behavior impairment of chronic stress induced-depression mice and it may be related to the upregulation of BDNF expression in the hippocampus.