OBJECTIVETo investigate the molecular mechanism of germ cell apoptosis following testicular torsion in rats.

METHODSHealthy male Sprague-Dawley rats (n = 16) were equally randomized into a control and a torsion group and the models of testicular torsion (720 degrees 2 h) were established. Twenty-four hours later, the apoptosis and count of germ cells were determined by flow cytometry, the expressions of Bax, Fas and Fas ligand (FasL) mRNA semiquantitatively analyzed by RT-PCR and the cytochrome C release detected by Western blot.

RESULTSCompared with the control group, there was an obvious increase in the number of apoptotic germ cells, a marked decrease in that of haploid and tetraploid cells and significantly up-regulated expressions of Bax and Fas/FasL mRNA in the torsion group (P <0.01). The Western blot analysis showed that the cytochrome C release was remarkably increased 24 hours after the detorsion. There were significant differences between the two groups (P <0.01).

CONCLUSIONThere are two major signaling pathways of cell apoptosis following testicular torsion, intercellular and intracellular. Up-regulated expressions of the apoptosis-related molecules Bax and Fas/FasL and increased cytochrome C release may play an important role in germ cell apoptosis following testicular torsion in rats.