Objective:To evaluate the effects of the Chinese herbal formula Wuzi Yanzong Pill(五子衍宗丸,WYP) on the spermatogenesis and specific secretory functions of Sertoli cells in rat model and to investigate the underlying mechanism.Methods:Five groups of male Sprague-Dawley rats including the control group,the model group,the low-dose WYP group,the medium-dose WYP group and the high-dose WYP group(5 in each group)were treated daily with vehicle,multiglycosides of Tripterygium wilfordii Hook f(GTW) either alone(20 mg/kg) or followed by WYP(0.5,1.0,or 2.0 g/kg daily),respectively for 30 days.Serum levels of follicle-stimulating hormone(FSH),inhibin B(INHB) and testosterone(T) were evaluated using enzyme-linked immunosorbent assay.Androgenbinding protein(ABP) gene expression and transferrin(TF) protein expression in testis tissue specimens of all rats were determined using real-time reverse transcriptase polymerase chain reaction and Western blotting analysis,respectively.Histopathologica! alterations in the testis were determined using Johnsen's score.Results:The toxicity of GTW towards Sertoli cell secretory functions and spermatogenesis was accompanied by increased serum FSH concentrations and decreased INHB and T concentrations.Upregulated ABP mRNA levels,and decreased TF protein expression and Johnsen's scores were detected in the model group compared with the control group(P<0.05 or P<0.01).Oral high-dose WYP administrations to GTW-treated rats effectively alleviated all of the GTWinduced changes in specific secretory functions of Sertoli cells(ABP,INHB and TF).Furthermore,serum T level and Johnsen's score of the testis increased greatly compared with the model group(P<0.01).Conclusion:WYP has the ability to improve the spermatogenesis,possibly through modulating the secretory proteins expression of Sertoli cells.