氨甲酰促红细胞生成素对糖尿病心肌梗死大鼠心功能的保护作用

Protective effect of carbamylated erythropoietin on cardiac function in diabetic myocardial infarction rats

目的探索氨甲酰促红细胞生成素(CEPO)对糖尿病心肌梗死大鼠心功能的保护作用,及其作用机制。方法腹腔一次性注射链脲佐菌素建立糖尿病心肌梗死模型,随机分为模型组、对照组、实验组和联合组,每组10只;另取10只大鼠仅穿缝线,不结扎,设为假手术组。术后24 h,假手术组和模型组均腹腔注射50μg·kg^(-1)0.9%NaCl,每周3次,连续4周+灌胃给予二甲基亚砜(DMSO)溶液0.5 mL,每天1次,连续2周;对照组灌胃给予20 mg·kg^(-1) SRI-011381,每天1次,连续2周+腹腔注射50μg·kg^(-1)0.9%NaCl,每周3次,连续4周;实验组给予腹腔注射50μg·kg^(-1) CEPO,每周3次,连续4周+灌胃给予DMSO溶液0.5 mL,每天1次,连续2周;联合组灌胃给予20 mg·kg^(-1) SRI-011381,每天1次,连续2周+腹腔注射50μg·kg^(-1) CEPO,每周3次,连续4周。用超声心动图检测心功能,用酶联免疫吸附实验法检测血清基质金属蛋白酶-2(MMP-2)含量,用Western blot法检测左心室组织中转化生长因子β1(TGF-β1)和Smad4蛋白的表达水平。结果实验组、对照组、联合组、模型组和假手术组的左心室射血分数分别为(63.34±7.12)%,(42.13±5.20)%,(52.75±6.03)%,(46.92±5.17)%和(75.21±6.23)%;血清MMP-2含量分别为(2.55±0.37),(4.59±0.61),(3.02±0.44),(3.87±0.42)和(1.98±0.23)ng·mL^(-1);TGF-β1蛋白相对表达水平分别为0.24±0.03,0.69±0.06,0.35±0.04,0.58±0.05和0.12±0.02;Smad4蛋白相对表达水平分别为0.23±0.04,0.65±0.03,0.34±0.05,0.48±0.05和0.11±0.02。实验组和对照组的上述指标分别与模型组和联合组比较,差异均有统计学意义(均P<0.05)。结论CEPO可改善糖尿病心肌梗死大鼠的心功能,抑制心室重构,减轻病理变化,推测其作用机制与抑制TGF-β1/Smads信号通路有关。

Objective To study the protective effect of carbamoyl erythropoietin(CEPO)on cardiac function in diabetic myocardial infarction rats and to explore the related mechanisms.Methods A one-time injection of streptozotocin into the abdominal cavity was used to establish a diabetic myocardial infarction model,which was randomly divided into model,control,experimental and combination groups with 10 rats per group.Ten rats only underwent sham operation and were set as sham-operation group.24 hours after operation,the sham-operation and model groups were intraperitoneally injected with 50μg·kg^(-1)0.9%NaCl,3 times a week,for 4 consecutive weeks+intragastric dimethyl sulfoxide(DMSO)solution 0.5 mL,once a day for 2 consecutive weeks.The control group was given intragastric infection of 20 mg·kg^(-1) SRI-011381 dissolved in DMSO 0.5 mL,once a day for 2 consecutive weeks+intraperitoneal injection of 50μg·kg^(-1)0.9%NaCl,3 times a week for 4 consecutive weeks.The experimental group was given intraperitoneal injection of 50μg·kg^(-1) CEPO,3 times a week for 4 consecutive weeks+intragastric DMSO solution 0.5 mL,once a day for two consecutive weeks.The combination group was given intragastric administration of 20 mg·kg^(-1)SRI-011381 dissolved in DMSO 0.5 mL,once a day for 2 consecutive weeks+intraperitoneal injection of 50μg·kg^(-1) CEPO,3 times a week for 4 consecutive weeks.The echocardiography was used to measure the cardiac function indexes.The serum matrix metalloproteinase-2(MMP-2)was detected by enzyme linked immunosorbent assay.Western blot was used to detect the relative expression of transforming growth factorβ1(TGF-β1),Smad4 proteins in left ventricular tissue.Results The left ventricular ejection fraction(LVEF)in the experimental,control,combination,model and sham-operation groups were(63.34±7.12)%,(42.13±5.20)%,(52.75±6.03)%,(46.92±5.17)%and(75.21±6.23)%;serum MMP-2 contents were(2.55±0.37),(4.59±0.61),(3.02±0.44),(3.87±0.42)and(1.98±0.23)ng·mL^(-1);the relative expression levels of TGF-β1 protein were 0.24±0.03,0.69±0.06,0.35±0.04,0.58±0.05 and 0.12±0.02;the relative expression levels of Smad4 protein were 0.23±0.04,0.65±0.03,0.34±0.05,0.48±0.05 and 0.11±0.02.The above indexes of the experimental and control groups were compared with those of model and combined groups,the differences were statistically significant(all P<0.05).Conclusion CEPO can improve the cardiac function of rats with diabetic myocardial infarction,inhibit ventricular remodeling,and reduce pathological changes,suggesting that the mechanism may be related to the inhibition of TGF-β1/Smads signaling pathway.