Smyd1与Sirt1在孕鼠肾上腺素应激模型新生鼠心脏中的表达变化

Changes of expressions of Smyd1 and Sirt1 in neonatal rat heart of epinephrine stress model of pregnant rats

目的观察组蛋白甲基化酶(Smyd1)与组蛋白去乙酰化酶(Sirt1)在妊娠晚期肾上腺素孕鼠应激模型中新生鼠心脏内的表达变化。方法 SPF级C57BL/6系孕鼠36只,随机分为A组(实验干预组)、B组(溶媒对照组)、C组(正常对照组),每组12只。A组和B组孕鼠于妊娠第12. 5天开始,分别每日腹腔注射肾上腺素200μg/kg及等量溶媒(双蒸水),连续7 d,并测量孕鼠血糖值。C组不作任何处理。3组孕鼠待其自然分娩,记录产仔数与新生鼠心质量(HW)、体质量(BW)。取新生鼠心肌组织,光镜观察心肌结构改变,PT-PCR及Western blot法检测新生鼠心肌细胞中Smyd1和Sirt1的mRNA及蛋白的表达水平。结果 A组新生鼠HW、心重指数(HW/BW)高于另外两组(P<0. 05)。光镜下A组新生鼠心肌细胞表现为心肌肌束排列紊乱,出现"核周光圈"现象,心肌组织内出现炎细胞浸润。A组Smyd1的mRNA及蛋白表达水平均增加,Sirt1的mRNA及蛋白表达下降,3组之间差异有统计学意义(P<0. 05),3组Smyd1与Sirt1表达之间存在负性相关关系(r=-0. 86,P<0. 05)。结论妊娠晚期孕鼠体内应激环境对新生鼠心脏影响明显,可引起新生鼠心肌细胞形态学变化,以及组蛋白甲基化酶Smyd1与组蛋白去乙酰化酶Sirt1表达水平的改变。

Objective To observe the changes of expressions of Smyd1 and Sirt1 in neonatal rat heart of epinephrine-induced stress model of pregnant rats. Methods Thirty-six SPF C57 BL/6 pregnant rats were randomly divided into A group( epinephrine treatment group),B group( solvent control group),and C group( normal control group),12 rats in each group. The pregnant women in A group and B group were treated by intraperitoneal injection of epinephrine( 200 μg/kg) and solvent of the same volume( double distilled water) from the 12. 5 th day of pregnancy,respectively,the treatment lasted for continuous seven days,plasma glucose levels were detected. The pregnant women in C group were not treated by any method. After spontaneous labor of pregnant rats in the three groups,the numbers of neonatal rats,neonatal rat heart weights( HW),and body weights( BW) in the three groups were recorded. Myocardial tissue samples of neonatal rats were obtained. Light microscope was used to observe changes of myocardial structure. RT-PCR and Western blot were used to detect the expression levels of Smyd1 and Sirt1 mRNA and proteins. Results HW and HW/BW in A group were statistically significantly higher than those in the other two groups( P< 0. 05). Disordered cardiac muscle bundles," perinuclear aperture" phenomenon,and inflammatory cell infiltration of myocardial tissue were observed by light microscope in A group. The expression levels of Smyd1 mRNA and protein in A group increased significantly,the expression levels of Sirt1 mRNA and protein decreased significantly,there were statistically significant differences among the three groups( P<0. 05). In the three groups,Smyd1 expression was negatively correlated with Sirt1 expression( r =-0. 86,P<0. 05). Conclusion Internal stress environment of late pregnant rats has significant impact on neonatal rat heart,which can induce morphological change of myometrial cells of neonatal rats and changes of expression levels of Smyd1 and Sirt1.