Expressions Of Smads In Mouse Testis After X-ray Total-body Irradiation

Transforming growth factor beta (TGF-β) superfamily and their receptors are expressed in the testis, and are believed to play important paracrine and autocrine roles during testicular development and spermatogenesis. The Smad proteins are downstream mediators for the superfamily of TGF-β. They play important roles in transducing the cytoplasmic signals from transmembrane receptors to the nucleus during the different stages of spermatogenesis. Within the testis, proliferating spermatogonia are the most radio-sensitive cell type, whereas spermatozoa and stem cell spermatogonia are relatively radio-resistant. Therefore, expression of the effects of radiation is both dependent on duration of time since exposure as well as dose exposure.DNA repair, cell cycle checkpoint fidelity and apoptosis are the common effect of postradiation lesions. One of the consequences of ionizing radiations on different cell types is a modulation of the production of different growth factors and cytokines. These factors could induce repair of postradiation lesions or enhance X-ray cell killing. Despite a complex signaling pathway involved in the physiological functions of male gonad, available information about the distribution and function of Smad proteins in the testis is extremely limited. Although, alterations in the function and expression of TGF-β. TGF-β...