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目的:研究观察胰岛素治疗对心肌梗死大鼠(myocardial infarction,MI)胶原重构的影响。方法:成年雄性SD大鼠34只,随机分为3组,即假手术(Sham)组(n=6)、生理盐水(NS)对照组(n=14)及胰岛素(ISL)治疗组[n=14,缺血20 min后,通过尾静脉以4 ml/(kg.h)的速率输入50 U/L ISL 2 h,并在缺血后1周内,每日皮下注射0.5 U/ml胰岛素1 ml/kg体质量]。分别于术后1周和4周,行心脏超声心动图(UCG)监测左室射血分数(LVEF),用氯胺T法检测心肌组织中羟脯氨酸(Hyp)的含量,用Western blot检测Ⅰ型胶原和Ⅲ型胶原蛋白的表达。结果:术后1周和4周时,对照组的LVEF值较Sham相比明显降低(P<0.01),而ISL治疗组与对照组相比,LVEF显著升高(P<0.05,P<0.01)。与Sham组相比,对照组心肌胶原的含量升高,ISL治疗组可使胶原的含量显著降低(P<0.05)。1周时,对照组的心肌Ⅰ/Ⅲ型胶原的比值增加,经ISL治疗后,Ⅰ/Ⅲ型胶原的比值明显下降(P<0.05);4周时,对照组Ⅰ/Ⅲ型胶原的比值增加,而给予ISL治疗后Ⅰ/Ⅲ型胶原的比值无明显差异。结论:MI后大鼠心肌非梗死区组织出现胶原重构,ISL可影响该过程中心肌Ⅰ/Ⅲ型胶原的比值,从而起到改善心脏功能的作用。
Objective: To observe the effect of insulin therapy on collagen remodeling in myocardial infarction (MI) rats. Methods: Thirty-four adult male Sprague-Dawley rats were randomly divided into three groups: sham group (n = 6), NS group (n = 14) and insulin group = 14, 20 min after ischemia, 50 U / L ISL was injected through the tail vein at a rate of 4 ml / (kg.h) for 2 h and subcutaneously injected with 0.5 U / ml insulin 1 ml / kg body weight]. Left ventricular ejection fraction (LVEF) was measured by echocardiography (UCG) at 1 week and 4 weeks after surgery respectively. The content of hydroxyproline (Hyp) in myocardium was detected by chloramine T method. The expressions of type I collagen and type III collagen were detected. Results: LVEF in control group was significantly lower than that in Sham at 1 week and 4 weeks after operation (P <0.01), but LVEF in ISL treated group was significantly higher than that in control group (P <0.05, P <0.01) ). Compared with Sham group, the content of myocardial collagen in control group increased, and the content of collagen in ISL treatment group decreased significantly (P <0.05). At 1 week, the ratio of type Ⅰ / Ⅲ collagen in the control group increased, and the ratio of type Ⅰ / Ⅲ collagen decreased significantly after ISL treatment (P <0.05). At 4 weeks, the ratio of type Ⅰ / Ⅲ collagen in control group Increase, while the ratio of type I / III collagen after ISL treatment had no significant difference. CONCLUSION: Collagen remodeling appears in non-infarcted myocardium of rats after MI. ISL can affect the ratio of type I / III collagen during the process of myocardial infarction, thus improving cardiac function.