Lei Zhang1, Xiujuan Gao1, Xin Yuan1, Huanli Dong1, Zongwang Zhang2, Shilei Wang3. 1. Department of Anesthesiology, Liaocheng People's Hospital, Liaocheng, Shandong, China. 2. Department of Anesthesiology, Liaocheng People's Hospital, Liaocheng, Shandong, China. Electronic address: zwzhang68@sina.com. 3. Department of Anesthesiology, Affiliated Hospital of Qingdao University Medical College, Qingdao, Shandong, China.
Abstract
BACKGROUND: It is reported that ischemic penumbra is a dynamic process, in which irreversible necrosis in the center of ischemia propagates to the neighboring tissue over time. Recent research has indicated that mitochondrial adenosine triphosphate (ATP)-sensitive potassium channels (mitoKATP) opener diazoxide plays an important role in cerebral protection; however, the role of mitochondrial calcium uniporter (MCU) in the effect of diazoxide on penumbra and infarct core remains unclear. METHODS: Adult male Wistar rats were randomly divided into 5 groups: the Sham group, the ischemia-reperfusion (I/R) group, the diazoxide and ischemia-reperfusion (Dzx + I/R) group, the diazoxide and spermine and ischemia-reperfusion (Dzx + Sper + I/R) group, and the spermine and ischemia-reperfusion (Sper + I/R) group. The animals were exposed to 24-hour reperfusion after 2-hour ischemia. Diazoxide and spermine were administrated at 30 minutes or 10 minutes before the beginning of ischemia or reperfusion, respectively. After 24-hour reperfusion, animals were given neurologic performance tests and when overdosed with general anesthesia their brains were excised for infarct volume, apoptosis, and immunohistochemical. RESULTS: Rats in the Dzx + I/R group displayed improved neurologic deficits, decreased infarct volume in cortex but not in subcortex, and apoptosis (evidenced by decreased terminal deoxynucleotidyl transferase-mediated dUTP nick end lebeling-positive percentage and the immunohistochemistry of cytochrome c) in cortex caused by ischemia/reperfusion. Rats in the Dzx + Sper + I/R group displayed worse neurologic deficits, larger infarct volume in cortex but not in subcortex, and more apoptosis both in penumbra and infarct core of cortex than those in the Dzx + I/R group. CONCLUSIONS: Results in our study suggested that diazoxide improved neurologic deficits, decreased infarct volume in cortex but not in subcortex, and apoptosis in cortex against ischemia/reperfusion injury is mediated by spermine.
BACKGROUND: It is reported that ischemic penumbra is a dynamic process, in which irreversible necrosis in the center of ischemia propagates to the neighboring tissue over time. Recent research has indicated that mitochondrial adenosine triphosphate (ATP)-sensitive potassium channels (mitoKATP) opener diazoxide plays an important role in cerebral protection; however, the role of mitochondrial calcium uniporter (MCU) in the effect of diazoxide on penumbra and infarct core remains unclear. METHODS: Adult male Wistar rats were randomly divided into 5 groups: the Sham group, the ischemia-reperfusion (I/R) group, the diazoxide and ischemia-reperfusion (Dzx + I/R) group, the diazoxide and spermine and ischemia-reperfusion (Dzx + Sper + I/R) group, and the spermine and ischemia-reperfusion (Sper + I/R) group. The animals were exposed to 24-hour reperfusion after 2-hour ischemia. Diazoxide and spermine were administrated at 30 minutes or 10 minutes before the beginning of ischemia or reperfusion, respectively. After 24-hour reperfusion, animals were given neurologic performance tests and when overdosed with general anesthesia their brains were excised for infarct volume, apoptosis, and immunohistochemical. RESULTS:Rats in the Dzx + I/R group displayed improved neurologic deficits, decreased infarct volume in cortex but not in subcortex, and apoptosis (evidenced by decreased terminal deoxynucleotidyl transferase-mediated dUTP nick end lebeling-positive percentage and the immunohistochemistry of cytochrome c) in cortex caused by ischemia/reperfusion. Rats in the Dzx + Sper + I/R group displayed worse neurologic deficits, larger infarct volume in cortex but not in subcortex, and more apoptosis both in penumbra and infarct core of cortex than those in the Dzx + I/R group. CONCLUSIONS: Results in our study suggested that diazoxide improved neurologic deficits, decreased infarct volume in cortex but not in subcortex, and apoptosis in cortex against ischemia/reperfusion injury is mediated by spermine.