Résumé
ObjectiveTo investigate the expression of thyrotropin-releasing hormone receptor (TRH-R) type-1and type-2 in ethane dimethanesulphonate (EDS)-treated rat testis, and to discuss the significance of its expression in Leydig cells.Methods To make the injured testis Leydig cells rat model with EDS treatment. Western blotting, immunohistochemical ABC and immunofluorescence double labeling methods were used to detect the expression and location of TRH-R1 and R2 in the testicular tissues of EDS-treated-day 2,day 7,day 14,day 21 and day 28 rat mode, respectively. Results Western blotting results showed that the positive immunochemical staining was not found in the testicular tissues of the EDS-treated day 2 to day 14, on the other hand,they were found in EDS-treated-21 day and EDS-treated-28 day. Immunohistochemistry demonstrated that TRH-R1 and R2 expressed in the spindle-shaped cells reappeared around seminiferous tubules of post-EDS 21 days and 28 days groups. Immunofluorescence double labeling confirmed that these TRH-R1 and R2 positively stained cells were newly regenerated progenitor Leydig cells.Conclusion TRH-R1 and R2 are involved in the regeneration of Leydig cells in EDS-treated rat testis, and they may exert functions in the proliferation and differentiation of adult type Leydig cells.
Résumé
By means of histological and immunohistochemical methods,effects of a singleintraperitoneal injection of ethane dimethanesulphonate(EDS,75 mg/kg bodyweight)on the hypothalamo-pituitary-testicular axis of the rat were observed inthis study.Three days after administration of EDS,Leydig cells were eliminated;some LH cells in pituitary became larger or decreased in immunoreactivity;but nosignificant change could be found in hypothalamic GnRH system.Seven days afterEDS,degeneration of spermatogenic epithelium was marked,the staining intensity ofLH cells was generally reduced,the number of GnRH immunorcactive neurons inthe hypothalamus as well as the density and staining intensity of GnRH fibers andterminals in the median eminence were significantly diminished.Testosteronereplacement increased the number of late spcrmatids in testis and restored theabove-mentioned changes in the hypothalamus and pituitary.These results indicate that following administration of EDS,1)spermatogenesisdamage is resulted from destruction of Leydig cells and cessation of testosterone secretion;2)respective hormone release from hypothalamic GnRH system andpituitary LH cells is increased;3)loss of testosterone negative feedback is themajor factor responsible for the enhancement of secretory activity of the hypotha-lamo-pituitary axis;and that 4)EDS can be a useful experimental tool forstudying hypothalamo-pituitary-testiculer axis and intratesticular local regulation.