ABSTRACT
Objective To evaluate the effect of hydrogen on mitochondrial fusion during myocardial ischemia-reperfusion (I/R) in aged rats.Methods One hundred and fifty pathogen-free healthy male Sprague-Dawley rats,aged 18 months old,weighing 400-500 g,were divided into 5 groups (n=30 each) using a random number table:control group (group C),sham operation group (group S),group I/R,normal saline group (group NS) and hydrogen-rich saline group (group H).Group C received no treatment.The anterior descending branch was only exposed but not ligated in group S.Myocardial I/R was induced by occlusion of the anterior descending branch of the left coronary artery for 30 rmin followed by reperfusion in I/R,NS and H groups.Hydrogen-rich saline 1 ml/100 g was injected intraperitoneally at 5 min before reperfusion in group H,while normal saline 1 ml/100 g was injected intraperitoneally at 5 min before reperfusion in group NS.The rats were sacrificed at 12 and 24 h of reperfusion,and hearts were removed for examination of the pathological changes and for determination of apoptosis in cardiomyocytes (by TUNEL) and expression of Mfn1 and Mfn2 protein and mRNA in myocardial tissues (by Western blot or real-time polymerase chain reaction).The apoptosis index was calculated.Results Compared with C and S groups,the apoptosis index of cardiomyocytes was significantly increased and the expression of Mfn1 and Mfn2 protein and mRNA in myocardial tissues was down-regulated at 12 and 24 h of reperfusion in I/R,NS and H groups (P＜0.05).Compared with NS and I/R groups,the apoptosis index of cardiomyocytes was significantly decreased and the expression of Mfn1 and Mfn2 protein and mRNA in myocardial tissues was up-regulated at 12 and 24 h of reperfusion in group H (P＜0.05).The pathological changes of myocardial tissues were significantly attenuated in group H when compared with group I/R.Conclusion The mechanism by which hydrogen attenuates myocardial I/R injury is related to promoting mitochondrial fusion and inhibiting apoptosis in cardiomyocytes of aged rats.