叶酸对高血糖孕鼠胎鼠心肌细胞凋亡的影响

目的建立妊娠期糖尿病大鼠模型,孕期予以叶酸干预,观察叶酸对胎鼠心肌细胞凋亡的影响。方法将30只SD孕鼠随机分为3组：DM组（妊娠期高血糖模型组）、DM＋FA组（妊娠期高血糖模型＋叶酸干预组）、正常对照组（正常妊娠组）,每组各10只。于妊娠第6天,DM组与DM＋FA组大鼠一次性腹腔注射新配制1%链脲佐菌素（STZ）50 mg.kg-1,正常对照组予等量的柠檬酸纳-柠檬酸缓冲液。从妊娠第7天开始DM组、DM＋FA组和正常对照组分别予等容量蒸馏水、叶酸（FA）1.2 mg.kg-1和等容量蒸馏水灌胃,直至妊娠结束。3组孕鼠均于妊娠第21日剖宫取胎,观察活胎数及死胎数,称量胎鼠体重,取胎鼠心脏制作标本。胎鼠心脏标本HE染色后光镜下观察组织结构的变化并计算病变积分,采用免疫组织化学法检测各组胎鼠心肌组织caspase-3蛋白表达,采用末端脱氧核苷酸转移酶介导的地高辛标记的dUTP缺口末端标记法（TUNEL法）检测各组胎鼠心肌细胞凋亡。结果①STZ干预前3组孕鼠血糖比较,差异无统计学意义（P〉0.05）,STZ干预后孕鼠血糖DM组、DM＋FA组与正常对照组相比,差异均有统计学意义（P〈0.01）,DM组与DM＋FA组相比,差异无统计学意义（P〉0.05）。②死胎率DM组、DM＋FA组均显著高于正常对照组（P〈0.01）,但DM＋FA组较DM组显著降低（P〈0.01）。胎鼠体质量：DM组和DM＋FA组均显著高于正常对照组（P〈0.01）,DM组和DM＋FA组比较差异无统计学意义（P〉0.05）。③光镜下胎鼠心肌组织病变积分、胎鼠心肌组织中caspase-3蛋白阳性表达的平均光密度值及胎鼠心肌细胞凋亡率DM组、DM＋FA组均显著高于正常对照组（P〈0.01）;但DM＋FA组较DM组显著降低（P〈0.01）。结论孕鼠妊娠期高血糖可引起胎鼠心肌细胞凋亡以及凋亡相关蛋白表达增多的改变,妊娠期补充叶酸对母鼠高血糖所导致的胎鼠心肌细胞凋亡有保护作用。

The Influence of Folic Acid to Fetal Heart Apoptosis of Hyperglycemia Pregnancy Rat

Objective To establish the Animal model of gestational diabetes rats which were intervened by folic acid during pregnancy.And to observe the influence of folic acid on fetal rat cardiomyocytes apoptosis.Methods Thirty SD pregnant rats were randomly divided into 3 groups：DM group（model group）,DM＋FA group（model plus folic acid intervention group）,and normal control group（normal pregnancy group）with 10 in each.On the gestational day 6,the rats of DM and DM＋FA groups were injected intraperitoneal with 50 mg·kg-1 of 1% streptozotocin（STZ）,while the animals in control group were injected with the equal dose of citrate buffer.From the gestational day 7 until the end of pregnancy,all animals in DM group,DM＋FA group and the control group were intragastriced respectively with same volume of distilled water,folic acid（FA）1.2 mg·kg-1 and distilled water daily.All rats were killed on the 21st day of pregnancy,observed numbers of live births and the stillbirth fetal weight were recorded,and the fetal hearts were collected.The fetal hearts were examined under light microscope after HE staining and observe the structure changes and calculate the lesion score,using immunohistochemistry to detect the expression of caspase-3 protein and using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling（TUNEL） to detect the cell apoptosis of fetal heart.Results ①The blood glucose of pregnant rats in the 3 groups showed no difference before intervening（P0.05）.There was significant difference between Groups DM and group normal cotrol,Group DM＋FA and group normal control after intervening（P0.01）,but no significant difference between Group DM and DM＋FA was found（P0.05）.②Stillbirth rate of DM group,DM＋FA group was significantly higher than normal control group（P0.01）,However,DM＋FA group was significnatly lower than DM group（P0.01）.The fetus in Group DM and DM＋FA was heavier than that in controls,with significant difference（P0.01）,but not between Group DM and DM＋FA（P0.05）.③The myocardial lesion score under light microscope,the mean optical density value of caspase-3 expression,and the rate of cardiomyocytes apoptosis,compared with control group,increased markedly in groups DM and DM＋FA（P0.01）;However,the above data were significantly lower in the Group DM＋FA compared with Group DM（P0.01）.Conclusion Pregnant hyperglycemia rats could show fetal cardiomyocytes apoptosis,as well as increase expression of apoptosis-related proteins.Folic Acid supplementation during pregnancy on the female rat could have a protective effect to the apoptosis of fetal cardiomyocytes.