The Effect of Mitochondrial Calcium Uniporter Opener Spermine on Diazoxide against Focal Cerebral Ischemia—Reperfusion Injury in Rats

Abstract

Recent research has indicated that mitochondrial adenosine triphosphate-sensitive potassium channels play an important role in cerebral protection, which involves in attenuating the calcium of mitochondria. However, the effect of diazoxide on cerebral ischemia-reperfusion and the role of spermine, the agonist of mitochondrial calcium uniporter (MCU), remain unknown. We investigated the effect of MCU opener spermine on diazoxide against focal cerebral ischemia-reperfusion injury in rats. Adult male Wistar rats were randomly dividedinto 5 groups: the Sham group, the I/R group, the Dzx+I/R group, the Dzx+Sper+I/R group, and the Sper+I/R group. Rats were exposed to 2-hour ischemia and 24-hour reperfusion. Diazoxide were administrated 30 minutes before ischemia, and spermine were given 10 minutes before reperfusion. Rats in the Sham group did not experience the process of ischemia-reperfusion. After 24-hour reperfusion, rats were given neurological performance tests, overdosed with general anesthesia, and then their brains were excised for infarct volume, pathological changes, and biochemical evaluation and analysis. Rats in the Dzx+I/R group displayed improved neurological deficits and decreased infarct volume and oxidative stress (evidenced by decreased nitric oxide and malondialdehyde but increased antioxidant enzymes [eg, glutathione peroxide and superoxide dismutase]) caused by ischemia-reperfusion. The beneficial effects of diazoxide were significantly attenuated by spermine treatment. Rats in the Sper+I/R group displayed worse neurological deficits, larger infarct volume and more oxidative stress, and less antioxidant enzymes than those in the Dzx+I/R. Our results suggested that diazoxide, which improved neurological deficits and decreased infarct volume and oxidative stress against ischemia-reperfusion injury, is mediated by spermine.