Efficacy of self-made Gengnian decoction on phosphatidylinositol 3-kinases/protein kinase B/mammalian target of rapamycin signaling pathway in perimenopausal rats.

OBJECTIVE

To investigate the efficacy of self-made Gengnian decoction on expressions of phosphatidylinositol 3-kinase (PI3K), protein kinase B (Akt) and mammalian target of rapamycin (mTOR) in ovarian tissues of perimenopausal rats. They were identified with symptom pattern of kidney-Yang deficiency in terms of Traditional Chinese Medicine.

METHODS

Female Sprague-Dawley rats aged 10-12 months were selected. Estrous cycle was observed by vaginal smears of keratinocytes to screen the perimenopausal model rats. The chosen rats were randomly divided into five groups, including perimenopausal model of kidney-Yang deficiency group (24 rats), self-made Gengnian decoction of high-dose group (24 rats), self-made Gengnian decoction of middle-dose group (24 rats), self-made Gengnian decoction of low dose group (24 rats) and tibolone control group (24 rats). In addition, rats aged 4-6 months were selected as young control group. The perimenopausal model rats of kidney-Yang deficiency were prepared by alternative intramuscular injection of hydrocortisone 5 mg·kg－1·d－1 The successfully prepared models in self-made Gengnian decoction of high-dose, middle-dose and low-dose groups and tibolone control group were given self-made Gengnian decoction 26.4, 13.2 and 6.6 mg·kg－1·d－1, and tibolone tablets solvent 0.22 mg·kg－1·d－1, respectively, through intragastric administration. Models group and young control group were given the same dose of normal saline, 1 time a day for 15 consecutive days. 24 h after the last administration, blood and ovarian tissues were collected after anesthesia with 20% ethyl carbamate. The follicles of different levels in ovarian tissue were observed and counted by histopathological hematoxylin-eosin staining. Enzyme linked immunosorbent assay was applied to test insulin-like growth factor-1 (IGF-1) level in the serum of experimental rats. The expression levels of PI3K, phosphorylated-Akt (p-Akt) and phosphorylated-mTOR (p-mTOR) mRNA in ovarian tissue were detected by quantitative real-time polymerase chain reaction.

RESULTS

The total follicle counts of perimenopausal model rats with kidney-Yang deficiency were significantly reduced, and the number of follicles (mainly increased in preantral follicles and antral follicles) in perimenopausal model rats with kidney-Yang deficiency was significantly increased after intervention of high and middle doses of Gengnian decoction and tibolone (P < 0.05). Compared with normal rats in young control group, the levels of IGF-1 in serum of perimenopausal rats with kidney-Yang deficiency were significantly decreased (P < 0.01), and those intervened by high dose of Gengnian decoction and tibolone were significantly up-regulated. The relative expression levels of PI3K, p-Akt, p-mTOR mRNA in ovarian tissues of perimenopausal rats with kidney-Yang deficiency were significantly lower than those of young rats (P < 0.01), and those intervened by high dose of Gengnian decoction and tibolone were significantly up-regulated (P < 0.05).

CONCLUSION

Self-made Gengnian decoction can increase the levels of IGF-1, PI3K, Akt and mTOR mRNA expression in serum.