Abstract: Objective　To investigate the regulatory effect of Yishen Tongluo Fang (YTF) on phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt) pathway in azoospermia/oligozoospermia model rats induced by cyclophosphamide (CP), and its protective mechanism. Methods　Male SD rats were randomly divided into blank control group (intragastric administration of normal saline), model group (intraperitoneal injection of DMSO solution), PI3K/Akt pathway inhibitor LY294002 group (LY group, intraperitoneal injection of 0.3 mg/kg LY), YTF low dose group (3 g/kg YTF), YTF high dose group (12 g/kg YTF) and YTF+LY group (intragastric administration of 12 g/kg YTF + intraperitoneal injection of 0.3 mg/kg LY),10 rats in each group. Except for control group, rats in other groups were intraperitoneally injected with CP to establish azoospermia/oligozoospermia model. After 4 weeks of continuous administration, bilateral testicular tissues were taken and testis index was measured. The pathological changes of testis were observed by hematoxylin eosin (HE) staining. The mean seminiferous tubular diameter (MSTD) was measured by image analysis system, and the development of spermatogenic epithelial cells was evaluated by Johnsen score. The serum levels of sex hormone testosterone (T) and follicle forming hormone (FSH) were detected by enzyme-linked immunosorbent assay (ELISA). Western blot assay was used to detect the expressions of PI3K/Akt pathway protein and downstream target protein rapamycin target molecule (mTOR) protein in testis. The relative expression levels of indexes of spermatogonia proliferation, differentiation and spermatogenesis, such as basic fibroblast growth factor (bFGF), promyelocytic leukemia zinc finger (PLZF) and transmembrane tyrosine kinase receptor (C-kit), were also measured. Results　Compared with the control group, the level of testis index and T level decreased, FSH level increased, MSTD, spermatogenic cell development score and expression levels of bFGF, PLZF, C-kit, PI3K, p-Akt/Akt and mTOR protein in testis decreased in the model group (P＜0.05). Compared with the model group, the level of testis index and T level increased, FSH level decreased, MSTD, spermatogenic cell development score and expression levels of bFGF, PLZF, C-kit, PI3K, p-Akt/Akt and mTOR protein in testis  increased in the YTF low and high dose groups (P＜0.05). The changes of the above indexes were more significant in the YTF high dose group than those in the YTF low dose group; while the changes of the above indexes in LY group were contrary to those in YTF low and high dose groups. There were no significant differences in changes of the above indexes between YTF+LY group and the model group. Conclusion　YTF may promote the proliferation and differentiation of spermatogonia and spermatogenesis by activating PI3K/Akt/mTOR pathway protein expression, and then improve spermatogenesis function in azoospermia/oligozoospermia rats.

Key words: azoospermia, oligospermia, phosphatidylinositol 3-kinase, cyclophosphamide, Yishen Tongluo Fang, phosphatidylinositol-3-kinase/protein kinase B pathway