MP43-19 EFFECT OF PHARMACOLOGICAL POST CONDITIONING ON ISCHEMIA-REPERFUSION INJURY IN THE RAT TESTIS

Abstract

INTRODUCTION AND OBJECTIVES: The effects of administered KATP channel openers or blockers during ischemia are still controversial in many organs/tissues. To examine whether the administration of KATP channel openers or blockers before or during ischemia ameliorates IR injury in the testis. METHODS: Eight-week-old male SD rats were subjected to 2 h right testicular ischemia followed by 24 h reperfusion. The selective mitochondrial (mito) KATP channel blocker, 5-hydroxydecanoate (5-HD) (40 mg/kg), non-selective KATP channel blocker glibenclamide (Glc) (5 mg/kg) or selective mito KATP channel opener diazoxide (DZ) (10 mg/kg), non-selective KATP channel opener cromakalim (Crom) (300 mg/kg) were administered intraperitoneally 15 min prior to the ischemia or 45 min before the induction of reperfusion. Tissue damage was evaluated by malondialdehyde concentration, myeloperoxidase activity, histological evaluation and TUNEL assay in the testis. RESULTS: There was a significant reduction in oxidative stress, neutrophil infiltration, histological score and apoptosis in the IR model in the testis when DZ and Crom were administrated before ischemia. However, this reduction was not seen with the administration of DZ or Crom during ischemia. In addition, there was a significant reduction in the testicular IR injury with the administration of Glc, but not 5-HD during ischemia. CONCLUSIONS: The pre-conditioning effect on IR injury in the testis was confirmed by treatment with DZ. The administration of non-selective KATP channel blocker Glc during ischemia ameliorated against the testicular IR injury. On the other hand, the selective mito KATP channel blocker, 5-HD and KATP channel openers during ischemia did not reduce the testicular IR injury. These data suggest that opening of KATP channel before ischemia, and blocking of the sarcolemmal KATP channel during the testicular ischemia may have a protective effect. Glc could be an effective drug to manage the post-ischemic injury after testicular torsiondetorsion injury. Source of Funding: A grant in aid from the Ministry of Education, Science, and Culture of Japan (#23118)