Abstract: Objective To investigate the expression of thyrotropinreleasing hormone receptor (TRH-R) type1 and 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 ar

Key words: Thyrotropinreleasing hormone receptor, Ethane dimethanesulphonate, Testis, Leydig cell, Western blotting, Immunohistochemistry, Rat