Effects of total saponins of panax notoginseng on depressive behavior and hippocampal nerve regeneration in rats with following global cerebral ischemia depression

Objective To explore the effect of the total saponins of panax notoginseng (TSPN) on depression-like behavior following global cerebral ischemia depression in rats and its mechanism. Methods Using four-vessel occlusion method to build the global cerebral ischemia model, then the cerebral ischemia rats were given solitary breeding with chronic unpredictable mild stress(CUMS) to prepare depression model.Seventy rats were divided into sham group (n=10), model group (n=20), PSD group (n=20) and TSPN group (n=20). The rats in the TSPN group were administered TSPN intraperitoneally 30 min post-brain ischemia.The dose of TSPN (75mg/kg) was suspended in 0.9% saline 10g/L, once per day for 30 days after reperfusion.While rats in the vehicle group and PSD group was treated with equal volume of 0.9% saline, one injection per day until the rats were sacrificed at 30 days after brain ischemia.The BrdU, doublecortin (DCX) expression in the hippocampus was assessed by immunohistochemistry. Results In comparison with the model group, the sucrose preference percentage in the PSD group was significantly lower ((46.2±9.2)%, (61.2±7.6)%; t=3.18, P<0.05), then the PSD rats were administered TSPN intraperitoneally, the sucrose preference percentage increased significantly ((62.4±3.4)%, (46.2±9.2)%; t=3.43, P<0.05). During the forced swimming test, the immobility time of PSD group was significantly increased compared with the model group ((119.4±9.7)s, (88.0±15.6)s ; t=4.30, P<0.01), while after PSD rats administering TSPN intraperitoneally, the immobility time was shorten remarkably ((97.4±6.7)s, (119.4±9.7)s; t=3.01, P<0.05). Compared with the Model group(BrdU+ : (12.6±2.2)/mm2, DCX+ : (38.6±4.2)/mm2), the number of BrdU+ and DCX+ cells in the SGZ of hippocampus in PSD group decreased (BrdU+ : (8.8±1.5)/mm2, DCX+ : (27.2±2.8)/mm2; t=3.25, 4.29, both P<0.01). And compared with PSD group, the number of BrdU+ and DCX+ cells in the SGZ of hippocampus in TSPN group increased significantly (BrdU+ : (14.8±2.8)/mm2, DCX+ : (37.0±3.3)/mm2; t=4.68, 3.69, both P<0.05). Conclusion TSPN can improve the depression-like behavior of rats following global cerebral ischemia, which may be related with promoting hippocampal nerve regeneration. Key words: Total saponins of panax notoginseng; Hippocampus; Nerve regeneration; Following global cerebral ischemia depression; Rats