N-乙酰半胱氨酸联合缺血后处理减轻糖尿病小鼠心肌缺血再灌注后肺损伤的作用研究

Effects of N-acetylcysteine combined with ischemic postconditioning on lung injury after myocardial ischemia-reperfusion in diabetes mice

目的研究N-乙酰半胱氨酸(NAC)联合缺血后处理(IPostC)对糖尿病小鼠心肌缺血再灌注后肺损伤的作用。方法选择15周龄雄性db/db糖尿病小鼠30只,分为假手术组(D-SO组,n=10)、心肌缺血/再灌注组(D-I/R组,n=10)和NAC联合缺血后处理组(D-NAC+IPostC组,n=10)。D-SO组小鼠开胸后不做任何处理;D-I/R组小鼠干预为冠状动脉左前降支结扎60 min,后复灌15 min。D-NAC+IPostC组在结扎冠状动脉左前降支前30 min腹腔注射NAC150 mg/kg,缺血后处理的干预方式为小鼠缺血60 min后即刻进行3个周期再灌注/缺血,然后再灌注15 min。于再灌注结束后颈动脉取血,检测血清C反应蛋白(CRP)、肿瘤坏死因子-α(TNF-α)、单核细胞趋化蛋白-1(MCP-1)水平,处死小鼠,取肺组织,检测湿干重(W/D)比值,光镜下观察肺组织病理形态学变化,计算肺损伤评分,测定肺组织氧化应激相关标志物谷胱甘肽(GSH)、超氧化物歧化酶(SOD)及丙二醛(MDA)水平,采用Western Blot法检测肺组织缺氧诱导因子1α(HIF-1α)和血管内皮生长因子(VEGF)的表达水平。结果与D-SO组比较,D-I/R组小鼠光镜下病理学损伤严重(P<0.05),肺W/D比值增加(P<0.05),血清TNF-α、CRP水平降低(P<0.05),MCP-1水平升高(P<0.05),肺组织MDA含量增加(P<0.05),SOD及GSH活性降低(P<0.05),肺组织HIF-1α及VEGF表达上调(P<0.05)。与D-I/R组比较,D-NAC+IPostC组肺组织镜下病理学损伤明显减轻(P<0.05),肺W/D比值降低(P<0.05),血清TNF-α、MCP-1水平降低(P<0.05),CRP水平升高(P<0.05),肺组织氧化应激因子MDA含量降低(P<0.05),抗氧化应激因子SOD及GSH活性升高(P<0.05),肺组织HIF-1α、血管内皮生长因子(VEGF)水平表达增高(P<0.05)。结论NAC联合IPostC可减轻糖尿病心肌缺血再灌注小鼠肺损伤,其机制可能与HIF-1α/VEGF信号通路相关。

Objective To investigate the effects of N-acetylcysteine(NAC)combined with ischemic postconditioning(IPostC)on myocardial ischemic reperfusion induced lung injury in diabetic mice.Methods 3015-week-old male db/db diabetic mice were divided into sham operation group(D-SO group,n=10),myocardial ischemia/reperfusion group(D-I/R group,n=10)and NAC combined with ischemic postconditioning group(DNAC+IPostC group,n=10).D-SO group mice did not receive any treatment after thoracotomy.D-I/R group was treated with left anterior descending coronary artery ligation for 60min andthenreperfusion for 15 min.In D-NAC+IPostC group,150 mg/kg NAC was intraperitoneally injected half an hour before ligation of the left anterior descending coronary artery.The intervention method of ischemia postconditioning was 3 cycles of reperfusion/ischemiaimmediately after 60min of ischemia,followed by 15min of reperfusion.Blood was collected from the abdominal aorta after reperfusion,and serum C-reactive protein(CRP),tumor necrosis factor-α(TNF-α)and monocyte chemotaxis protein-1(MCP-1)levels were detected.Mice were sacrificed;lung tissues were collected;and wet-dry weight(W/D)ratio was detected.The pathological changes of lung tissues were observed under light microscope,and lung injury scores were calculated.The levels of superoxide dismutase(SOD),glutathione(GSH)and malondialdehyde(MDA)of oxidative stress-related markers in lung tissue were determined.The expressions of hypoxia-inducing factor 1α(HIF-1α)and vascular endothelial growth factor(VEGF)in lung tissue were detected by Western Blot.Results Compared with D-SO group,pathological injury of D-I/R group was serious under light microscope(P<0.05);lung W/D ratio was increased(P<0.05);serum TNF-αand CRP were decreased(P<0.05);MCP-1 level was increased(P<0.05);and MDA content in lung tissue was increased(P<0.05);SOD and GSH activities were decreased(P<0.05);HIF-1αand VEGF expression were increased(P<0.05).Compared with D-I/R group,pathological injury of lung tissue in D-NAC+IPostC group was significantly reduced under microscope(P<0.05);lung W/D ratio was decreased(P<0.05);serum TNF-αand MCP-1 were decreased(P<0.05);CRP was increased(P<0.05).The content of oxidative stress factor MDA was decreased(P<0.05),the activities of antioxidant stress factors SOD and GSH were increased(P<0.05),and the expressions of HIF-1αand vascular endothelial growth factor(VEGF)were increased(P<0.05).Conclusion NAC combined with IPostC can reduce lung injury after myocardial I/R in diabetic mice,and the mechanism may be related to HIF-1α/VEGF signaling pathway.