The effect of total saponins of Panax notoginseng on learning and memory of rats with post stroke depression and its mechanism / 中华行为医学与脑科学杂志

ABSTRACT

Objective:To investigate the effect of total saponins of Panax notoginseng (TSPN) on learning and memory of post-stroke depression (PSD) rats and its mechanism.Methods:Four-vessel occlusion method was used to build the rat stroke model and 7 days later these rats were given solitary breeding with chronic unpredictable mild stress (CUMS) to make depression model. Rats were randomly divided into Sham group ( n=10), Model group ( n=10), PSD group ( n=10) and TSPN group ( n=10). The rats in the Model group and PSD group were injected administered with equal volume of 0.9% saline 30 min post-brain ischemia, one injection per day for 30 days. while TSPN group were treated with TSPN. The dose of TSPN (75 mg/kg) was dissolved in 0.9% saline 10 g/L, once per day for 30 days. Then the learning and memory of rats were tested by Morris water maze.The protein levels of DCX and Nestin in the hippocampus were detected by Western blot. Furthermore, the DCX/Ki67 co-labeled cells in the SGZ of hippocampus were observed by the immunofluorescence. Results:The escape latency at the fifth day of PSD group((31.8±3.8)s) was longer than that in the Sham group((10.4±3.2)s) and Model group((19.8±3.7)s) ( t=9.23, 5.15; both P<0.05). The escape latency ((14.2±2.8)s) of TSPN group was shortened significantly than PSD group ( t=8.56, P<0.05). The times across the platform in the Sham group was (10.3±1.7), and the PSD group was (4.1±1.1), difference was statistically significant between two groups( t=11.24, P<0.05). The times across the platform (8.4±1.6) of TSPN group statistically increased compared with PSD group ( t=5.77, P<0.05). The protein levels of DCX and Nestin in the PSD group were (0.60±0.02), (0.58±0.03) respectively, and in the TSPN group were (1.07±0.07), (0.95±0.11) correspondingly, there were significant differences of the DCX, Nestin protein level between the two groups( t=20.22, 7.68, both P<0.01). Moreover, there was significant difference in the number of the DCX/Ki67cells in the hippocampus SGZ between the PSD group((16.2±2.8) /mm 2) and TSPN group ((21.2±3.1) /mm 2)( t=2.42, P<0.05). Conclusion:TSPN could improve the learning and memory of the rats with post-stroke depression through enhancing the hippocampus neurogenesis.