| Objective:To investigate gender difference in ischemia-reperfusion (IR) induced myocardialinjury in rats and the mechanisms of this phenomenon.Methods:Male and female Sprague-Dawley rats were used in the present study. Rats weredivided into four groups: male sham group, male ischemia-reperfusion group, femalesham group, female ischemia-reperfusion group. Evans-blue and TTC staining methodwere used to detect ratio of myocardial infarct area to risk area, tissue section stainmethod to detect cell apoptosis in myocardial, western-blot was used to detectexpressions of myocardial tissue apoptosis-related proteins Bcl-2, Bax, phosphor-p38and autophagy-related protein LC-3B.Results:1. Ratio of infarct area to risk area in male rats was higher than in female ratsafter cardiac ischemia-reperfusionEvans-blue and TTC staining data illustrated that ligation of male and female ratsleft anterior descending coronary artery for30min and reperfusion24h, male rats,average ratio of infarct area to risk area in male rats was30.7±3.4％, and in female rateswas8.1±1.3％(P<0.05）.2. Apoptosis in male and female rats after cardiac ischemia-reperfusionDetection of apoptosis show myocardial tissue sections under the microscope afterstain, the apoptotic cells in male rats was significantly higher than in female rats（P<0.05）.3. Expressions of apoptosis-related proteins after cardiacischemia-reperfusion. 3.1Expression of anti-apoptotic protein: Bcl-2Under physiological conditions, male rats myocardial tissue anti-apoptotic Bcl-2expression was significantly higher than female rats (P<0.05). However，ischemia-reperfusion significantly reduced Bcl2expression in male rats (P<0.05), butnot in female rats (P>0.05)..3.2Expression of pro-apoptotic protein: Bax and p38Under physiological conditions, expressions of pro-apoptotic related protein Baxwere not significantly different between male rats myocardial tissue and female ratsmyocardial tissue (P>0.05). However， ischemia-reperfusion significantly reduced Baxexpression in female rats (P<0.05), but not in male rats (P>0.05).Under physiological conditions, phospho-p38expression in male and female ratswere not significantly different (P>0.05), after ischemia-reperfusion phospho-p38expression significantly increased in male rats (P<0.05), but not in female rats (P>0.05).3.3Ratio of anti-apoptotic related protein Bcl-2to pro-apoptotic relatedprotein Bax in male and female rats after cardiac ischemia-reperfusionCorresponding ratio of Bcl2to Bax was calculated in each group, male rat heartsshowed higher Bcl2to Bax ratio than female rat hearts both in physiological (P<0.05)and pathological (P<0.05) conditions, this ratio did not markedly change after IR bothin male and female rat hearts.4. Expression of autophagy-related protein expression after cardiacischemia-reperfusion.Expression of autophagy protein levels was calculated by the ratio of LC3B toLC3A. Under physiological conditions, the ratio of LC3B to LC3A was similar in maleand female rat hearts; however, male rat hearts showed significantly decrease of theratio after IR (P<0.05), but female rat hearts showed markedly increase of the ratio(P<0.05). Thereafter, the ratio of LC3B to LC3A was significantly higher in female rathearts compared with male rat hearts in pathological conditions (P<0.05)..Conclusion:1. Ischemia-reperfusion induced myocardial injury in male rats was significantlyhigher than in female rats. 2. The existence of such differences may be due to the decline of anti-apoptoticrelated protein in male rats and pro-apoptotic related protein in female rats, and thedifferent regulating patterns of autophagy related protein. |
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