[Protective effects of L-carnitine upon testicular ischemia-reperfusion damage in rats]

To investigate the protective effects of L-carnitine upon testicular ischemia-reperfusion injury in rats.

Sprague-Dawley rats were divided into 3 groups (n = 10). In those animals undergoing unilateral testicular torsion, right testes were rotated 720 degrees for 2 h. Sham operated group served as a control group. Torsion group underwent 2 h torsion and saline was injected intraperitoneally at 30 min pre-detorsion. Treatment group underwent similar torsion but L-carnitine (500 mg/kg) was infused intraoperatively. The right testes of 5 animals in each group were excised after 4 h reperfusion for measuring the levels of malondialdehyde (MDA) and heat shock protein 70 (HSP70), evaluation of activities of antioxidant enzyme including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). Histopathological changes and germ cell apoptosis indices (AI) were determined at 24 h post-detorsion in right testes of the remaining 5 animals in each group.

The mean number of apoptotic nuclei per tubule cross section and the malondialdehyde level were significantly lower in treatment group as compared with torsion group [AI( 6.87 +/- 2.47) vs (17.13 +/- 3.56), MDA (160 +/- 15) vs (199 +/- 15) nmol/g]. Activities of antioxidant enzyme and the level of HSP70 were significantly higher in treatment group than those in torsion group [SOD (1638 +/- 153) vs (1078 158) U/g, CAT (317 +/- 28) vs (188 +/- 33) U/g, GPx (667 +/- 94) vs (311 +/- 65) U/g, HSP70 (0.87 +/- 0.13) vs (0.25 +/- 0.04)]. The pathological damage of testes in the treatment group was lighter than that in the torsion group (all P < 0.05).

The administration of L-carnitine exerts a beneficial effect upon testicular ischemia-reperfusion injury. This effect may be achieved through an induced expression of HSP70.