妊娠糖尿病母鼠其胎儿心脏P38 MAPK的表达及意义

Expression of P38 MAPK in fetal hearts of the gestational diabetes mellitus rats and its significance

目的:了解p38丝裂原活化蛋白激酶(p38 mitogen-activated protein kinase,P38 MAPK)在妊娠糖尿病(gestational diabetes mellitus,GDM)母鼠胎儿心脏中的表达规律,旨在探讨其与妊娠期糖尿病母鼠其婴儿发育异常的内在联系。方法:取成年雌性SD大鼠随机分成两组,通过阴道涂片确定怀孕后分别注射链脲佐菌素(streptozoto-cin,STZ)及柠檬酸-柠檬酸钠缓冲液,建立GDM组和对照组,给药后72 h隔天测血糖及体质量。两组大鼠分别于孕后第12、15、19 d随机抽取剖宫,进行胎鼠心脏取材,HE染色观察心脏组织病理变化,免疫组化检测P38 MAPK的蛋白表达量,荧光定量PCR方法检测心脏组织P38 MAPK mRNA的表达。结果:①对照组子鼠心脏发育情况正常,未见心肌壁异常增厚、房室间隔病理性缺损及动脉圆锥干畸形等异常情况。高倍镜下可见心肌细胞呈椭圆形,胞浆丰富,核大,形态规则,染色均匀。GDM组12、15、19 d均可见子鼠心脏发育异常,包括室间隔缺损、圆锥干发育畸形、心肌异常肥厚及心腔扩大等,高倍镜下可见12、15 d心肌细胞结构较清晰,细胞肿胀,胞浆溶解,胞核形态尚规则,细胞结构不清。19 d细胞可见胞浆溶解,成片的无结构区,胞核形态不规则。②第12、15、19 d GDM组p38MAPK蛋白在胎鼠心肌细胞胞浆中的表达显著增强,与相应时间点的对照组相比均明显增高,在GDM组中,以第12 d的表达最强。③第12、15、19 d GDM组胎鼠心脏组织中p38 MAPK mRNA的相对表达量明显高于相应时间点的对照组。结论:妊娠糖尿病母鼠其胎鼠心脏发育异常的发生率明显升高。p38 MAPK蛋白及mRNA在妊娠糖尿病胎鼠孕12、15、19 d三个观察点的心脏表达水平明显增高,提示其可能参与妊娠糖尿病致心脏发育异常的过程。

Aim：To master p38 mitogen-activated protein kinase （p38 MAPK） expression in the heart of neonatal rats of gestational diabetes meUitus rats mother, and exploring the internal relationship with p38MAPK of the heart developmental defect in the infant of diabetic mothers, and further elaborated the mechanisms of the heart developmental defect in the infant of diabetic mothers. Methods： The Sprague- Dawley female rats were randomly divided into GDM group and control group, determined by vaginal smears after pregnancy, the female rats in GDM group were injected with STZ at belly cavity and the fe- male rats in control group were injected with PBS in the same position. 72 hours after administration both groups were detected blood grucose and body weight every one day. Two groups of pregnant rats were ran-domly selected after cesarean 12,15,19days, all rats were uterine-incision delivery and got the embryo heart tissues. Observing the pathological diagnosis of heart tissues by HE stain, The expression of p38 MAPK in heart tissues were analyzed by Immunohistochemical techniques. And also examined the expres- sion of p38 MAPK messenger ribonucleic acid （mRNA） in heart tissues by fluorescent real-time RT- PCR. Results： The heart development of control group fetal rats is normal, there is no abnormal thicken- ing of myocardial wall, no pathological septal defect, nor arterial cone anomalies. Under micrcoscope with the high power lens, myocardial cells are oval shapes, and abundant of cytoplasm, large neuclear, regular and uniform dyeing. There are more at embryo heart development defect numbers at diabetes group than those of the control group, there exists obvious statistics difference, major including caul-co- nus development malformation （ VSD）, ntrieular septal cleft （VSC） and myocardial hypertrophy, abnor- mality of the heart chamber, and so on. Under high-powered microscope it showed that the myocardial cell structure of 12, and 15d are not so clear,there exists cell swelling and cytoplasmic dissolution. The nu- cleus shape is still regular,yet the eell structure is not clear. In the 19 d myocardial cells, it can be seen the cytoplasm was dissolved into a piece of non-structural areas, and the nucleus had irregular shapes; The protein expression of p38 MAPK in myocardial cells were stronger on the pregnant days of 12,15 ,and 19 in GDM group, the difference was significant compared with control group. And its highest expression was on the pregnant days of 12. The expression of p38 MAPK mRNA in the fetal heart of GDM group were significantly higher than control group on the pregnant days of 12,15, and 19. Conclusion： Maternal gestational diabetes can cause abnormal fetal heart development, p38 MAPK protein and mRNA in gesta- tional diabetes pregnancy 12,15,19 days of fetal cardiac expression were significantly increased, sugges- ting that p38 MAPK may be involved in the process caused by abnormal heart development in gestational diabetes.