Proliferação das células de Sertoli na região de transição entre os túbulos seminíferos e a rete testis em ratos Wistar

Abstract

The transition region corresponds to the segment of the seminiferous tubules that connects to the rete testis. Recently, special attention has been focused on this unique testicular parenchyma area taking into account the presence of undifferentiated cells and singular interactions with immune system cells. The present thesis was elaborated in order to better characterize morpho-functionally the transition region, specially related to its Sertoli cell population. Then, using several important functional markers, a phenotypic evaluation was performed on Sertoli cells located in the transition region in Wistar rats. Unlike the established paradigm in literature, our results showed that rat Sertoli cells located in the transition region exhibit a distinct functional phenotype and retain the proliferative capacity into adulthood. In subsequent studies, a pre-pubertal transient hypothyroidism was induced via PTU treatment in order to evaluate the effects on the Sertoli cells proliferation/differentiation dynamics. Using this approach and based on the known mitotic capacity of the Sertoli cells located in the transition region, it was possible to stimulate the proliferation of these cells and significantly increase several key testis parameters related to sperm output, such as the total number of Sertoli cells per testis and testis weight. In conclusion, the transition region seems to harbor pools of progenitor Sertoli cells and emerges as an important area to stimulate growth in length of the seminiferous tubules and maximize testis function.