Abstract:

Objective To investigate the effects of pretreatment with acanthopanax senticousus saponins (ASS) on learning and memory ability and cholinergic neurons following fimbrial transection in rats. Methods Twenty-seven SD rats were randomly divided into ASS pretreatment group, ASS treatment group and control group, with 9 rats in each group. After right-side hippocampal fimbrial transection, 0.5 mL/100 g normal saline and 100 mg/kg ASS were intraperitoneally injected per day in control group and ASS treatment group respectively for 6 weeks. In ASS pretreatment group, rats were treated with intraperitoneal injection of 100 mg/kg ASS per day for 2 weeks before right-side hippocampal fimbrial transaction and for 4 weeks after operation. Seven weeks and eight weeks after fimbrial transection, dark avoidance test and passive and active avoidance test were conducted respectively in all groups. Nine weeks after fimbrial transection, septal area brain sections were obtained, immunohistochemical staining of nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) and choline acetyltransferase (ChAT) was performed, and the numbers, areas and circumferences of nitric oxide synthetase (NOS) and ChAT positive neurons were analysed. Results The acquisition frequency and retention time in dark avoidance test and the positive rates of active and total avoidance reaction in passive and active avoidance test in ASS pretreatment group were superior to those in ASS treatment group and control group (P<0.05). The retention time in dark avoidance test in ASS treatment group was significantly longer than that in control group (P<0.05). The numbers, areas and circumferences of NOS and ChAT positive neurons on the side of fimbrial transection in ASS pretreatment group were significantly greater than those in ASS treatment group and control group (P<0.05). The areas and circumferences of NOS and ChAT positive neurons on the side of fimbrial transection in ASS treatment group were significantly greater than those in control group (P<0.05). Conclusion Pretreatment with ASS may improve the learning and memory ability following fimbrial transection in rats, which may be associated with the protection of cholinergic neurons in septal area.

Key words: acanthopanax senticousus saponins, learning and memory, hippocampal fimbria, nitric oxide synthetase, choline acetyltransferase, rat