Aim: Spermatogenic dysfunction may result from thickening of seminiferous tubular basement membrane (BM) with tubular sclerosis. Transforming growth factor b1 (TGF-b1) plays an important role in fibrogenesis. The intracellular and extracellular expression of TGF-b1 in the testis were immunohistochemically determined, using LC antibody (LC) for intracellular TGF-b1 and CC antibody (CC) for extracellular TGF-b1. Methods: Twenty-three testicular biopsy specimens were obtained from varicocele and five from Sertoli-cell-only (SCO) patients, and five from normal volunteers. The relative area involved by the expression of TGF-b1 for CC or LC (TGF-b1 index for CC or LC) was examined, and semen parameters and serum hormonal levels and TGF-b1 were analyzed. The Johnson score (JS), the BM thickness, and the tubular diameter were also determined. Results: Immunoreactivity for CC was hardly detected. That for LC was detected in the Sertoli and germ cells. The TGF-b1 index for LC was significantly higher in the varicoceles than in the normal testes. Interestingly, that for LC was significantly higher in the varicoceles than in the SCO. The level of serum TGF-b1 was significantly higher in varicoceles than in the normal testes. Conclusion: The distribution of the intracellular and extracellular expression of TGF-b1 in human testis was demonstrated. It suggests that TGF-b1 is related to fibrosis of seminiferous tubules and may lead to spermatogenic disruption.

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