剖宫产出生仔鼠脑组织中胶质纤维酸性蛋白表达变化及神经元细胞凋亡检测

Alterations of glial fibrillary acidic protein expression and neural apoptosis in brain of rat offspring born by cesarean section

目的 探讨剖宫产出生的仔鼠海马和额叶皮质区胶质纤维酸性蛋白（GFAP）的表达变化以及神经元细胞凋亡情况.方法 将38只SD孕鼠自确定受孕时起随机分为2组：阴道产组19只和剖宫产组19只.阴道产组不进行任何处理,剖宫产组于孕第21天剖宫取仔鼠.阴道产组仔鼠48只和剖宫产组仔鼠40只,分别于出生后30、115 d处死仔鼠取脑组织,采用免疫组织化学（免疫组化）EnVision染色法分析单位面积中GFAP阳性染色细胞数量,蛋白印迹法定量检测两组仔鼠海马和额叶皮质区GFAP的表达;用末端转移酶标记染色法检测神经元细胞凋亡情况.结果 （1）GFAP表达：仔鼠出生后115 d,海马区GFAP阳性染色细胞数：阴道产组为（29.7±10.9）个,剖宫产组为（36.2±2.8）个,两组比较,差异有统计学意义（P＜0.05）;额叶皮质区GFAP阳性染色细胞数：阴道产组为（23.2±4.6）个,剖宫产组为（36.8±5.9）个,两组比较,差异也有统计学意义（P＜0.01）.仔鼠出生后30 d,额叶皮质区GFAP阳性染色细胞数：阴道产组为（27.8±6.0）个,剖宫产组为（39.4±4.5）个,两组比较,差异有统计学意义（P＜0.01）;海马区GFAP阳性染色细胞数：阴道产组为（31.5±3.5）个,剖宫产组为（37.2±7.0）个,两组比较,差异无统计学意义（P＞0.05）.蛋白印迹法检测阴道产组及剖宫产组仔鼠海马及额叶皮质区GFAP蛋白的表达比较,差异无统计学意义（P＞0.05）.（2）神经元细胞凋亡情况：仔鼠生后115 d,剖宫产组仔鼠海马区凋亡细胞零星分布,阴道产组海马区未见凋亡细胞.结论 剖宫产术对不同年龄段仔鼠的海马和皮质区GFAP表达有不同影响,可导致海马、额叶皮质区GFAP蛋白表达上调,海马区甚至出现细胞凋亡.

Objective To study changes of glial fibrillary acidic protein （GFAP） expression and neural apoptosis in rat hippocampus and cortex of cesarean delivered offspring.Methods Thirty-eight pregnant SD rats were randomly allocated into 2 groups： 19 rats in vaginal delivery （VD） and 19 rats in cesarean section （CS）.Forty-eight fetuses born by VD were kept intact, 40 fetuses were delivered by CS on day 21 of gestation.The fetal brain tissues were taken out on postnatal day 30 and 115, the expression profiles of GFAP in hippocampus and cortex were measured by immunohistochemical staining and western blot Apoptotic cells were detected using terminal deoxynucleotidyl transferase dUTP nick end labeling （TUNEL） staining.Results （1） The expression profiles of GFAP： on postnatal day 115, the mean number of GFAP-immunoreactive astrocytes of hippocampus 29.7 ± 10.9 in VD group was significantly lower than 36.2 ± 2.8 in CS group （ P 〈 0.05 ）.The average GFAP-positive cells in the cortex of frontal lobe of 23.2 ±4.6 in VD group was significantly lower than 36.8 ± 5.9 in CS group （P 〈0.01 ）.Likewise, on postnatal day 30, the mean number of GFAP-immunoreactive astrocytes of frontal cortex of 27.8 ± 6.0 in VD group was remarkably lower than 39.4 ± 4.5 in CS group （ P 〈 0.01 ）.The average GFAP-positive cells in the hippocampus of 31.5 ±3.5 in VD group were not significantly lower than 37.2 ±7.0 in CS group （ P 〉0.05 ）.The expression of GFAP was detected in hippocampus and frontal cortex by western blot, however,there was no significant different expression of GFAP between VD group and CS group.（2） Neuronal apoptosis： TUNEL staining results indicated that, on postnatal day 115, fewer apoptotic cells scattered in offspring hippocampas subregion were only shown in CS group, never in VD group.No TUNEL positive staining cells were labeled in hippocampal subregion in VD group, therefore significantly lower than that of CS group （ P 〈 0.05 ）.Conclusions There were different influences of cesarean section on GFAP expression in hippocampus or cortex in different developmental stage of offspring Cesarean section might increase GFAP expression in the hippocampus and frontal cortex, even trigger neuronal apoptosis of hippocampus region.