Objective:To investigate the protective effects and mechanisms of Ginkgo biloba extract (EGb) on rotenone-induced damage in PC12 cells, a pheochromocytoma cell line derived from rat adrenal medulla.Methods:PC12 cells were divided into blank control group, rotenone model group (0.5 μmol/L rotenone) and EGb761 group (0.5 μmol/L rotenone+ 100 mg/L EGb761). Mitochondrial membrane potential was detected by JC-1 probe. Mitochondrial energy metabolism levels were measured using a Seahorse XFe24 analyzer. Furthermore, protein expression levels of caspase-3, cleaved-caspase-3, adenosine monophosphate-activated protein kinase(AMPK), phosphorylated-AMPK (p-AMPK), phosphatidylinositol-3-kinase(PI3K), phosphorylated-PI3K(p-PI3K), serine/threonine-protein kinase (AKT), phosphorylated-AKT(p-AKT), mammalian target of rapamycin (mTOR), and phosphorylated-mTOR (p-mTOR) were determined by Western blot.SPSS 20.0 software was used for data analysis.One-way ANOVA was used for multiple group comparisons and LSD test was used for further pairwise comparisons.Results:(1) JC-1 staining showed statistically significant differences in the mitochondrial membrane potential of PC12 cells among the three groups ( F=34.89, P<0.05). EGb761 significantly increased the mitochondrial membrane potential in PC12 cells compared to the rotenone model group (fluorescence intensity ratio: (1.30±0.16), (0.81±0.15), P<0.05). (2) Seahorse experiments showed statistically significant differences in the basal respiration, ATP production, maximal respiration and spare respiratory capacity of PC12 cells among the three groups ( F=38.07, 64.18, 64.42, 34.62, all P<0.05). EGb761 significantly increased the basal respiration ((73.02±13.81)pmol/min, (33.69±3.91)pmol/min), ATP production ((57.08±7.31)pmol/min, (18.08±2.50)pmol/min), maximal respiration ((177.70±17.14)pmol/min, (113.12±13.24)pmol/min), and spare respiratory capacity ((104.72±8.58)pmol/min, (79.43±9.35)pmol/min) of PC12 cells compared to the rotenone model group (all P<0.05). (3) Western blot showed statistically significant differences in the ratio of cleaved-caspase-3/caspase-3、p-AMPK/AMPK、p-PI3K/PI3K、p-AKT/AKT、p-mTOR/mTOR in PC12 cells among the three groups ( F=48.05, 28.68, 33.73, 45.81, 17.39, all P<0.05). EGb761 significantly decreased the ratio of cleaved-caspase-3/caspase-3 ((1.95±0.36), (3.56±0.37)) and p-AMPK/AMPK((1.49±0.19), (2.25±0.27)) and increased the ratio of p-PI3K/PI3K((0.75±0.07), (0.44±0.07)), p-AKT/AKT((0.74±0.06), (0.36±0.09)), and p-mTOR/mTOR((0.90±0.06), (0.62±0.07)) in PC12 cells compared to the rotenone model group (all P<0.05). Conclusion:EGb761 has a protective effect on rotenone-induced PC12 cells, which was associated with the inhibition of AMPK activation and the PI3K/AKT/mTOR pathway, increasing mitochondrial activity and inhibiting apoptosis.

Objective:To document any effect of environmental enrichment on nerve regeneration in a mouse model of sciatic nerve compression and explore its mechanism.Methods:A crushed sciatic nerve model was successfully established in 22 C57BL/6 mice, and they were then randomly divided into an intervention group and a control group. The mice of the intervention group were raised in a cage with an enriched environment, while those of the control group were kept in a standard cage. Two weeks later, both groups′ gait was analyzed and the compound muscle action potential (CMAP) of the sciatic nerve was measured. The proportion of myelinated sciatic nerve fibers was examined using toluidine blue staining, and the expression of myelin basic protein (MBP), growth associated protein-43 (GAP43) and p75 neurotrophin receptor (p75 NTR) was measured using immunofluorescence intensity. Results:①The latency of the CMAP [(1.05±0.04)ms] was significantly shortened in the intervention group compared with the control group and the amplitude was significantly higher. ②Gait analysis showed a significant increase in the average contact intensity, stride length and stride rate of the intervention group compared with the control group. However, the step axis angle of the intervention group was significantly smaller than in the control group on average. ③The stained nerve fibers in the intervention group were orderly and dense, and the average number of myelinated fibers was significantly greater than in the control group. ④Quantitative analysis of the immunofluorescence showed that the levels of MBP, GAP43 and p75 NTR in the sciatic nerves of the intervention group were, on average, significantly higher than in the control group. Conclusion:An enriched environmental can promote the regeneration and functional recovery of crushed sciatic nerves by promoting the proliferation and myelination of Schwann cells.