Nrf2参与MSCs调节大鼠梗死心肌氧化应激作用的实验研究

Effect of Nrf2 in the Modulation of MSCs on Oxidative Stress in Rats with Myocardial Infarction

目的 探讨间充质干细胞（MSCs）移植对梗死心肌组织氧化应激反应的调节作用及其机制.方法 建立心肌梗死大鼠模型,利用随机数字表进行随机化分组,分为对照组（n=20）、MSC移植组（n=20）和MSC移植＋HO-1抑制剂组（n=20）.以密度梯度离心并贴壁培养获得骨髓源MSCs,于心肌梗死模型建立后经心肌局部多点注射MSCs悬液;细胞移植后不同时间点以测定血浆以及心肌梗死和梗死交界区组织超氧化物歧化酶（SOD）、还原型谷酰甘肽（GSH）和丙二醛（MDA）水平;Western Blot检测Nrf2和HO-1蛋白表达的变化.结果 细胞移植后8 h,3组大鼠梗死组织中SOD、GSH表达量开始下降,72 h时达到最低,以后逐渐开始回升,至两周时恢复接近心肌梗死前水平;同时,细胞移植后梗死组织中脂质氧化终产物MDA水平开始增高,3组均在72 h达到高峰（P〈0.05）,以后开始下降,至2周时降至梗死前水平.细胞移植后各时间点,与对照组比较,MSC移植组SOD和GSH含量下降幅度减小、恢复较快（P〈0.05）,且MDA含量减少（P〈0.05）.对照组梗死心肌组织中Nrf2及HO-1蛋白表达轻微升高,72 h时最显著;而MSC移植组中Nrf2和HO-1蛋白表达显著增高,且升高时间提前至细胞移植后24～72 h,且与对照组比较,细胞移植后24 h和72 h,Nrf2和HO-1表达水平均高于对照组（P〈0.05）;MSC移植＋HO-1抑制剂组与对照组比较,差异无统计学意义（P〉0.05）.结论 心肌梗死后移植MSCs可能通过促进局部Nrf2及其下游抗氧化酶靶基因HO-1蛋白表达而调节梗死心肌的氧化应激反应,进而减轻氧化应激诱导的心肌损伤.

Objective To explore the effect and its mechanism of nuclear factor erythroid 2 - related factor 2 （Nrf2） in the regula- tion of mesenehymal stem cells （MSCs） on oxidative stress in rat models with myocardial infarction. Methods Sixty rats were in- duced with myocardial infarction and divided into three groups： control group（n= 20）, MSC group（n= 20） and MSC plus an inhibitor group. Bone marrow derived MSCs were obtained with density gradient centrifugation and adherent culture,and were injected into in- fracted myocardium, superoxide dismutase （SOD）, glutathione peroxidase （GSH） and malondialdehyde （MDA） in the plasma and infracted myocardium were measured with Kit in different time point after transplantation. The expressions of Nrf2 and heine oxygen- ase - I（HO - 1）were detected with western blot. Results In three groups,the levels of SOD and GSH decreased in 8 h,the lowest in 72 h and then rose to the baseline level in 2 weeks after cell transplantation. Meanwhile, the level of MDA in the infracted myocardium increases, the highest in 72h,and then decreases the baseline in 2 weeks after cell transplantation in three groups. Compared with con- trol group,the levels of SOD and GSH in MSC group fall slightly and recover quicker,and the level of MDA decreases） The expres- sions of Nrf2 and HO - 1 in the control group increase slightly,the highest in 72 h. Compared with that in control group,the expres- sions of Nrf2 and HO - 1 protein were earlier and higher in 24 h and 72 h after cell transplantation. There was no different in both MSC ＋ an inhibitor group and control group. Conclusion MSCs have the effect of the regulation of oxidative stress in the infracted myocardium through the up - expression of Nrf2 and its downstream target gene such as HO - 1 protein and of contribution to myo cardial injury induced by oxidative stress.