OBJECTIVETo evaluate the effect of Gengnianchun Recipe (GNC) on learning memory function and its regulatory effect on hippocampal cholinergic system in ovariectomized rats.

METHODSFemale rats 10-12 months old were randomized into 5 groups, the sham-operation group, the model group treated with normal saline, the positive control group treated with Nilestriol, and the two GNC groups treated with high and low dose GNC respectively. A little fat around ovary was cut in the sham-operation group. The treatment lasted for 12 weeks after ovariectomy. Changes of learning memory function were tested by Morris water maze; serum level of estradiol (E2) was measured by chemical fluorescent method; hippocampal acetylcholinesterase (AChE) mRNA was determined with Real-time PCR; and the activities of acetylcholine (ACh), AChE and choline acetyltransferase (ChAT) in hippocampus were detected by immunohistochemistry respectively.

RESULTSTwelve weeks after ovariectomy, serum E2 and learning memory function markedly decreased in the ovariectomized rats (P < 0.01, P < 0.05). Nilestriol and high dose GNC showed an effect in improving the symptoms of learning memory functional deprivation and elevating the activities of hippocampal ACh, AChE and ChAT (all P < 0.05).

CONCLUSIONGNC can improve learning memory function of ovariectomized rats, and its mechanism might be realized by regulating the cholinergic system in hippocampus.