胎儿期至性成熟期持续暴露双酚A影响雌鼠卵巢核糖体功能

Continuous exposure to bisphenol A from fetal to sexual maturity affects ovarian ribosome function in female mice

双酚A(BPA)是一种常见的环境类雌激素,对动物产生生殖毒性。为了探究长期双酚A暴露对卵巢发育的影响,将孕0 d昆明小鼠(8周龄,体质量25~30 g,SPF级)随机分为7组,每组4个重复,每个重复5只。A组每天饮水给予蒸馏水(0.00 mg/kg BPA)作为对照组,B组每天饮水给与0.05 mg/kg BPA,C组每天饮水给与0.50 mg/kg BPA,D组每天饮水给与5.00 mg/kg BPA,E组每天饮水给与10.00 mg/kg BPA,F组每天饮水给与20.00 mg/kg BPA,G组每天饮水给与50.00 mg/kg BPA。BPA饮水自母鼠孕0 d到仔鼠45 d性成熟,共计63 d。结果显示,BPA剂量≥0.50 mg/kg时,仔鼠血清和卵巢中BPA含量显著增加(P<0.05),但仔鼠卵巢器官指数均无显著变化和病理损伤。TUNEL结果显示,染毒BPA≥10.00 mg/kg时卵巢颗粒细胞发生细胞凋亡(P<0.05)。当染毒BPA剂量≥0.50 mg/kg时仔鼠卵巢ERα表达量显著增多(P<0.05);低剂量BPA (0.05~10.00 mg/kg)显著降低ERβ表达,较高剂量(20.00~50.00 mg/kg)显著增加ERβ表达。转录组测序结果显示,BPA影响了卵巢核糖体通路,其中核糖体蛋白L21、Sa表达基因显著下调,核糖体蛋白L3、S2、L7a、S26、L26表达基因显著上调。这些基因的改变可能会导致胚胎生殖系统发育受阻和卵巢早熟。荧光定量PCR验证了转录组结果。本研究证实长期低剂量BPA暴露不会导致性成熟期小鼠卵巢器官指数变化和明显病理损伤,但会导致卵巢细胞凋亡和ER表达异常,BPA的生殖毒性可能与核糖体功能蛋白表达异常有关。

Bisphenol A(BPA)is a common environmental estrogen that produces reproductive toxicity to animals.In order to investigate the effect of long-term expose to bisphenol A on ovarian development,Kunming mice(8 weeks old,weight 25-30 g,SPF grade)were randomly divided into 7 groups of 4 replicates each,5 mice of replicate each.Group A was given distilled water as control group,Group B,C,D,E,F and G was given water containing 0.05,0.50,5.00,10.00,20.00,50.00 mg/kg BPA,respectively.BPA exposure to the dams was from gestation day 0(GD 0)to the end of lactation and from day 21 to day 45 to the offspring mice.The results showed that the BPA contents in the serum and ovarian tissue of the offspring mice were significantly increased when the dose of BPA was above 0.50 mg/kg body weight(P<0.05).However,there was no significant change in the ovarian index and pathological damages in the ovary.TUNEL assay showed that ovarian granulosa cells developed apoptosis when BPA was greater than or equal to 10.00 mg/kg(P<0.05).The results of immunohistochemistry showed that the expression of ERαin the ovary of the offspring mice was significantly increased when the dose of BPA was above 0.50 mg/kg(P<0.05).For ERβ,low dose(0.05 to 10.00 mg/kg)significantly reduced ERβexpression,and higher doses(20.00 to 50.00 mg/kg)significantly increased ERβexpression.The transcriptome sequencing results showed that BPA affected the ovarian ribosomal pathway,in which the ribosomal L21 and Sa genes were significantly down-regulated,and the ribosomal L3,S2,L7 a,S26 and L26 genes were significantly up-regulated.Real-time PCR validated the results of transcriptome sequencing.This study indicates that long-term exposure to low doses of BPA does not cause changes in ovarian organ index and obvious pathological damage,but it leads to abnormal apoptosis and ER expressions.This reproductive toxicity of BPA may be related to disrupted expressions of ribosome genes.