Objective To investigate the changes of heme oxygenase-1 (HO-l)/carbon monoxide system in myocardium of old rats. Methods Healthy male old and young SD rats were divided into four groups:old lipopolysacchride(LPS) group(n = 8) , old control group(n = 7), young LPS group(n= 12),young control group(n=12). LPS was given(3 mg/kg) intravenously with a bolus injection. Content of CO in plasma and HO-1 in myocardium determined by immunohistochemical analysis were measured 4 hours after injection. The histological and ultrastructure changes were observed under light microscope and electron microscope. Results The level of CO in plasma increased significantly in old and young LPS groups compare with old and young control groups (P<0. 05). Compared with old LPS group,the level of CO in plasma was decreased significantly in young LPS group(P<0. 05). After injection of LPS both old and young groups presented degeneration of myocardial cells, mild dilatation and hyperemia of capillaries in interstitium. The changes in old rats were much more severe than those in young rats. HO-1 level of myocardium in LPS groups was higher than that in control groups (P<0. 05). The positive staining of HO-1 in myocardium of old LPS rats was stronger than that of young LPS rats(P<0. 05). Conclusion After injection of. LPS, the injury of myocardium in old rat was much more severe than that in young rat. The expression of HO-1/CO system in myocardium of old LPS group was stronger than that of young LPS group,which may have relationships with severe protein denaturation and intensive oxidative stress in myocardium.%目的 探讨内毒素血症时老年大鼠心肌血红素氧合酶1(HO-1)和CO系统的变化.方法 39只SD大鼠分为老年对照组7只、青年对照组12只、老年内毒素组8只、青年内毒素组12只.采用尾静脉注射脂多糖(3mg/kg)制备内毒素模型,4h后取血及心脏,检测血浆CO水平；光镜及电镜观察心肌病理改变；免疫组织化学法检测心肌HO-1的表达.结果 与老年对照组和青年对照组比较,老年内毒素组和青年内毒素组CO水平明显升高(P＜0.05)；与老年内毒素组比较,青年内毒素组CO水平明显降低(P＜0.05).注射脂多糖后,老年和青年内毒素组大鼠均出现心肌细胞变性,间质毛细血管轻度扩张充血等病变,但老年组较青年组更严重.与青年内毒素组比较,老年内毒素组HO-1A值明显升高(P＜0.05).结论 内毒素血症时,老年大鼠心肌更容易受到损伤.HO-1/CO系统在老年内毒素组的表达更加明显,可能与其心肌细胞内蛋白变性严重、存在更加强烈的氧化应激有关.
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