RESUMEN
<p><b>OBJECTIVE</b>To study the localization and distribution of expressions of Smads (mother against dpp), the intracellular signal transduction molecules in the transforming growth factor-beta (TGF-beta) family, in the testis of male sterile rats with Shen-yang deficiency induced by adenine and to observe the effect of Wenyang Shengjing Decoction (WSD) on these expressions.</p><p><b>METHODS</b>Rats were randomly divided into the control group, the model group and the WSD group. Localization and distribution of Smad 1, Smad 2 and Smad 4 expressions were detected by immunohistochemistry SABC and semi-quantitative RT-PCR and analyzed statistically by image analysis system; the contents of testosterone (T), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) were detected by radioimmunoassay; and the weights of body, testis and epididymis, as well as sperm number of rats were also measured.</p><p><b>RESULTS</b>Smad 1 and Smad 2 were expressed in cytoplasm of all levels of spermatogenic cells in rats' testis with their positive immuno-responsive substance locating in the cytoplasm, and positive Smad 2 expression could also be found in cytoplasm of Sertoli's cell, but both of them showed negative response in Leydig's cell; Smad 4 was positively expressed in cytoplasm of Leydig's cell but showed negative response in spermatogenic cell and Sertoli's cell. Compared with the normal control, Smad 1 expression was lower (P < 0.05), but Smad 2 and Smad 4 were higher in the model group (both P < 0.05), these abnormal changes could be reversed by WSD treatment (all P < 0.05). Compared with the normal control group, the body weight, sperm number and serum T level were lower, and levels of FSH and LH were higher (all P < 0.05) in the model group, which could all be improved by WSD (P < 0.05); the weights of testis and epididymis were unchanged in all groups (P > 0.05).</p><p><b>CONCLUSION</b>WSD could not only increase the sperm number through elevating serum T level and decreasing the levels of FSH and LH, but also by way of regulating Smads genes expression to adjust the levels of sex hormones, promote the production of sperm directly or indirectly, so as to treat male infertility.</p>