Effects of inhibition of adenosine monophosphate-activated protein kinase on expressions of cytochrome c and caspase-3 and neuronal apoptosis in the cerebral cortex after cerebral ischemia-reperfusion injury in mice

Abstract

Objective To investigate the effects of inhibition of adenosine monophosphate-activated protein kinase (AMPK) on expressions of cytochrome c (CytC) and caspase-3 and apoptosis in the cerebral cortex after cerebral ischemia-reperfusion injury in mice. Methods Thirty-six male C57BL/6 mice were randomly divided into three groups, a sham operation group, a ischemia-reperfusion group, and a AMPK inhibitor group, 12 in each group. A model of middle cerebral artery occlusion was induced by suture method. The AMPK inhibitor compound C (20 mg/kg) was injected intraperitoneally in the AMPK inhibitor group, the equal volume normal saline was injected intraperitoneally in the sham operation group and the ischemia-reperfusion group when a thread was inserted. Immunohistochemical staining was used to detect the expression levels of CytC and caspase-3 and TUNEL method was used to detect apoptosis at 24 h after ischemia-reperfusion. Results Compared with the ischemia-reperfusion group, the numbers of CytC (28.86±9.65/HP vs. 58.86±9.65/HP; t=7.615, P=0.030) and caspase-3 (7.16±5.85/HP vs. 14.36±7.85/HP; t=2.548, P=0.035), and TUNEL (67.14±8.55/HP vs. 95.00±13.51/HP; t=6.891, P=0.030) positive cells in the cerebral cortex were reduced significantly in the AMPK inhibitor group. Conclusion Inhibition of AMPK activity after cerebral ischemia-reperfusion may decrease apoptosis by downregulating the expressions of CytC and caspase-3, and play a neuroprotective effect. Key words: Brain Ischemia; Reperfusion Injury; AMP-Activated Protein Kinases; Apoptosis; Caspase 3; Cytochromes c; Neuroprotective Agents; Mice