2011, 30(02): 152-157.
ObjectiveTo investigate the effects of recombinant human erythropoietin (rHuEPO) at different doses on myocardial apoptosis and Mfn2 protein expression in rats with myocardial infarction. MethodsA total of 64 adult SpragueDawley rats were used and divided randomly into 4 groups: myocardial infarction (MI) rats, which were treated with 5 000 U8226;kg-1 loading dose followed by a maintenance dose of 1 500 U8226;kg-1 for 1 week of rHuEPO (MITH) ( high dose ), and low dose of MITL(a loading dose followed by a maintenance dose of 750 U8226;kg-1 for 1 week), respectively, and sham eperated rats. Twentyfour hours and 2 weeks after operation, myocardial apoptosis was assessed by in situ terminal deoxynucleotidyl transferase(TdT)dUTP nickend labeling (TUNEL staining) and Mfn2 protein expression was measured with immunohistochemistry staining. ResultsTwentyfour hours after operation, apoptosis index (AI) in sham operated, MI, MITH and MITL rats was 0, （60.99±5.28）,（36.97±2.68） and （38.10±3.41）, respectively; mean optical density (MOD) of Mfn2 protein in four groups was （0.080 6±0.0134）, （0.295 2±0.024 9）, （0.125 3±0.020 9） and （0.120 2±0.019 7）, respectively. Two weeks after operation, AI in sham operated, MI, MITH and MITL rats was 0, （50.08±8.00）, （26.54±2.97） and （24.16±3.74）; MOD of Mfn2 protein in four groups was （0.095 3±0.007 3）, （0.247 3±0.019 1）, （0.146 1±0.012 6） and （0.154 2±0.010 6）. Twentyfour hours and 2 weeks after operation, AI and Mfn2 protein expression in MI rats were remarkably increased in comparison with sham rats (P＜0.05), and those in MITH rats were significantly decreased in comparison with MI rats (P＜0.05). There was no significant difference in apoptosis and Mfn2 protein expression between MITH group and MITL group (P＞0.05). ConclusionImmediately loading dose followed by a maintenance (one week) lower dose of rHuEPO can significantly reduce apoptosis and mitofusin 2 protein expression in rat myocardium after acute myocardial infarction. No significant difference in the effects by rHuEPO on Mfn2 protein expression and apoptosis was observed between high and low dose maintenance treatments.