Alternative und integrative Medizin

Effects of Zuogui Wan and Yougui Wan on the Expression of Learning- and Memory-related Signal Transduction Molecules

Abstract

Xiangping Kang, Chao Liang, Guoqin Jin, Xueli Zhang, Zhangbin Gong, Yanwu Xu and Zhifen Han

Objective: This study aimed to determine the effect of kidney-tonifying recipe Zuogui Wan (ZGW) and Yougui Wan (YGW) on learning and memory ability, serum corticosterone (CORT), and expression of learning- and memory-related signal transduction molecules in aging rats. Methods: Naturally aged rats (23 months) were used as animal model and were randomly divided into four groups: senile control group, senile+antagonist RU486 (antagonist of GR group, senile+ZGW group, and senile +YGW group). A fifth group was designated as the young group, composed of five-month old rats. Starting from the 21st month, rats of senile+ZGW and senile+YGW group were administered with ZGW and YGW respectively for three months. For subcutaneous injection, RU486 (5 mg/kg body weight) was administered 2 h prior to the Morris maze test (senile+antagonist RU486 group). Spatial learning and memory abilities were observed using Morris water maze test. Contents of serum CORT were examined using enzyme-linked immunosorbent assay. Expression of related signal transduction molecules (CaM, pCaMK II, pERK1/2, pCREB, Arc, and pSynapsin I) were tested using Western blot. Regulating effects of kidney-tonifying recipe and RU486 on above-mentioned indicators were also studied. Results: Contents of corticosterone in serum of senile rats were significantly higher compared with the young group. Morris water maze test showed that spatial learning and memory abilities of aging rats were clearly reduced. Expression of learning- and memory-related signal transduction molecules was also visibly lowered. However, kidney-tonifying recipe and RU486 exhibited potential to improve abnormal changes of the above-mentioned indicators in senile rats to varying extent. Conclusion: Experimental findings indicate that kidney-tonifying recipe and RU486 may improve spatial learning and memory abilities and retard the effects of aging on senile rats by down-regulating abnormally high corticosterone levels and up-regulating expression of related signal transduction proteins.