Aim: To study the effect of Ureaplasma urealyticum (UU) infection on germ cell apoptosis of male rats. Methods: Male rats were infected artificially with UU serotype 8 (T960) . Morphological changes of germ cells in the seminiferous tubules and the lumen of the epididymides were observed under the light microscope. Fluorescence-conjugated polyclonal antibodies to Fas and Fas ligand (FasL) were used to localize Fas and FasL. TUNEL staining of germ cells and Sertoli cells was performed by the AKPase method. TUNEL-positive rate ( % positive cells) and TUNEL-positive area (area occupied by stained cells) were analysed by KS400 Image Analysis System. The DNA laddering analysis was performed by agarose gels electrophoresis. Results: In those rats infected with UU: (1) Exfoliated germ cells were dramatically increased. Many multinucleated giant cells were found in the seminiferous tubules and the lumen of the epididymides. (2) The number of TUNEL-positive cells and the TUNEL-positive area were significantly increased.(3) The expression of Fas and FasL in germ cells and Sertoli cells was up-regulated. (4) Discrete bands of fragmented DNA were found in the testicular cells. Conclusion: In male rats, germ cell apoptosis was increased in UU infection.
