镉影响大鼠胎盘发育及Bcl-2和Bax的表达

Effect of exposure to cadmium during pregnancy on the morphological structure and the expression of Bcl-2 and Bax on rat placenta

目的通过观察镉暴露后胎盘组织形态结构和凋亡相关蛋白表达量的改变,探讨镉对胎盘组织中细胞增殖与凋亡的影响。方法将孕6天(E6)的20只孕鼠随机分成染镉组和对照组,染镉组一次性腹腔注射氯化镉,剂量为2mgCd/kg体重。两组的孕鼠分别于E14和E18断椎处死,每只孕鼠随机取出6个胎盘,制备石蜡切片。行HE染色观察染镉后胎盘的形态改变,免疫组织化学技术显示镉对Bcl-2和Bax表达的影响。结果染镉组胎盘海绵带滋养层细胞、巨细胞和空泡化细胞增多,且迷路带及海绵带滋养细胞呈退行性改变。染镉组胎盘组织细胞中的Bcl-2蛋白表达量比相应的对照组表达量明显降低(E14:t=7.067,P<0.01;E18:t=6.988,P<0.01);Bax蛋白表达量比相应的对照组表达量明显增多(E14:t=4.008,P<0.01;E18:t=4.732,P<0.01);Bcl-2/Bax比值与相应对照组之间的差异有统计学意义(E14:t=9.517,P<0.05;E18:t=23.380,P<0.01)。结论镉可以通过影响Bcl-2和Bax的表达,改变Bcl-2/Bax比值,使胎盘组织细胞的增殖和凋亡平衡紊乱,导致胎盘发育异常。

Objective： To observe cadmium - induced dysplasia of skeleton on rat embryos. Methods ： Pregnant rats （ embryo 6） were divided into 2 groups. The rats of the experimental group were treated by intraperitoneal injection with a single dose of 2 mg Cd/kg body weight. Control rats received only saline. The pregnant rats were killed at the 14th and 18th day of gestation respectively, and their placentas were taken out and selected 6 placentas per rat randomly, and tissue samples were embedded in paraffin. The effects of cadmium to rat placenta were observed by level of microscopy. Immunohistochemistry staining was used to observe the expression of Bcl 2 and Bax in placental tissue. Results ： In the experimental group s of cadmium poisoned rats, the placenta showed focus necrosis in the deciduas, and increased the trophoblastic giant cells and light staining cells in the trophospongium. Trophoblast in the labyrinth and trophospongium showed degeneration. The expression of bax gene in experimental groups was significantly higher than that in accordingcontrol groups （ E14 ： t = 4. 008, P 〈 0. 01 ; E18 ： t = 4. 732, P 〈 0. 01 ） . There was a lower expression of bcl - 2 gene in experimen-tal groups than that in the according control groups （ E14 ： t = 7. 067, P 〈0. 01 ; E18 ： t = 6. 988, P 〈 0. 01 ） . And the ratio of bax/bcl -2 was higher in the experimental groups than that in the according control groups （E14： t = 9. 517, P 〈0. 05; E18： t = 23. 380, P 〈 0. 01 ）. Conclusion ： Cadmium could affect the expression of bel - 2 and bax, increase the ratio of bax / bcl - 2, damage the balance between cell proliferation and apoptosis, lead to placental dysplasia.