Brief ischaemia reduces testicular lipid peroxidation following susequent ischaemia: An evidence for ischaemic preconditioning

Abstract

Brief periods of ischaemia followed by reperfusion protect tissues like the brain and heart from subsequent ischaemic episodes. Similar effects in the testis has not been adequately studied despite the fact that the testis is subject to ischaemia-reperfusion phenomena of clinical importance during testicular torsion. The present study was designed to investigate whether the testis exhibits ischaemic pre-conditioning. In the first part of the experiment, 85 adult male Sprague-Dawley rats were divided into five groups. In the first group, testicular malondialdehyde levels was determined as the control. In four groups, right sided testicular torsion was induced by twisting the testes and spermatic cord in a counter-clockwise direction through 720 degrees for 15, 30, 45 and 60 minutes. Five of the animals in each group had testes removed for determination of MDA levels, while the remaining had torted testes de-torted and orchidopexied. After 2, 4 and 6 weeks, five animals in each group had the right testes again twisted through 7200 for 15, 30, 45 and 60 minutes and de-torted. Animals were then sacrificed and testes collected for estimation of MDA. In the second part of the experiment, the above procedure was repeated except that intra-peritoneal melatonin 1 mg/kg was administered before de-torsion. Following retorsion after two weeks, MDA levels were significantly reduced from the control after 30, 45 and 60 minutes of torsion but not after 15 minutes of torsion. There was no significant difference between testicular MDA levels at initial torsion and subsequent levels following re-torsion if melatonin was administered at initial torsion. The testis exhibits ischaemic preconditioning which is abolished by melatonin.