摘要
[背景]诸多研究证实苯并[a]芘(BaP)可透过胎盘屏障及血脑屏障引起胚胎神经毒性,而目前关于外源化合物对BaP暴露所致健康损害的干预作用研究鲜有报道。氯化锂(LiCl)在临床上广泛应用于情绪调节,具有神经营养和神经元保护作用。[目的]探讨LiCl对孕期BaP暴露致大鼠胚胎发育及海马神经元损伤的改善作用,为研究其具体作用机制提供实验依据。[方法]10周龄孕期SD大鼠随机分为5组,分别为对照组、植物油组、BaP组(20 mg·kg^(-1)BaP)、LiCl组(40 mg·kg^(-1)LiCl)及LiCl干预组(20 mg·kg^(-1)BaP+40 mg·kg^(-1)LiCl),每组6只。妊娠第8天(GD8)开始灌胃染毒,1次·d^(-1),连续7 d至妊娠第14天(GD14),每天记录孕鼠体重。妊娠第18天(GD18)剖腹取出胎鼠,记录胎鼠总数、体重、身长及尾长;HE染色观察胎鼠海马神经元形态;Western blotting检测胎鼠海马组织糖原合酶激酶-3β(GSK-3β)、pGSK-3β、β-catenin蛋白表达。[结果]实验期间,对照组、植物油组和LiCl组孕鼠体重及胎鼠发育指标差异均无统计学意义(P>0.05)。GD14和GD18,BaP组孕鼠体重[(323.34±5.71)g、(364.34±10.41)g]均低于对照组[(339.17±7.10)g、(390.32±11.35)g](P<0.05),而LiCl干预组孕鼠体重[(345.05±7.72)g、(398.73±12.32)g]均高于Ba P组(P<0.05)。Ba P组胎鼠的体重、身长、尾长分别为(2.325±0.061)g、(3.072±0.077)cm、(1.135±0.068)cm,均低于对照组的相应指标值[(2.563±0.091)g、(3.284±0.078)cm、(1.276±0.041)cm](P<0.05);LiCl干预组胎鼠上述发育指标值为(2.669±0.096)g、(3.356±0.107)cm、(1.206±0.041)cm,均较BaP组有上升(P<0.05)。形态学观察发现,BaP组胎鼠海马组织齿状回区出现神经元皱缩和染色加深,LiCl干预组有改善。Western blotting结果显示:与对照组相比,BaP组pGSK-3β表达降低(对照组和BaP组的灰度值比值分别为0.87±0.04、0.50±0.04,F=19.64,P<0.001),GSK-3β表达升高(对照组和BaP组的灰度值比值分别为1.53±0.14、2.09±0.11,F=5.90,P=0.011),β-catenin表达降低(对照组和BaP组的灰度值比值分别为1.41±0.14、0.90±0.04,F=11.16,P=0.001);LiCl干预可明显逆转由BaP暴露引起的pGSK-3β表达降低、GSK-3β表达升高及β-catenin表达降低的现象(灰度值比值分别为:pGSK-3β,0.69±0.08,P=0.036;GSK-3β,1.59±0.15,P=0.042;β-catenin,1.33±0.08,P=0.006)。[结论]LiCl干预可改善孕期BaP暴露诱导的大鼠胚胎生长发育迟缓及海马神经元损伤,其机制可能与LiCl抑制GSK-3β活性进而提高β-catenin的表达相关。
[Background]Many studies have confirmed that benzo[a]pyrene(BaP)can cause embryo neurotoxicity through placental barrier and blood-brain barrier,but there are few reports about the potential interventive effect of xenobiotics on BaP induced health damage.Lithium chloride is widely used in clinical emotion regulation,with neurotrophic and neuroprotective effects.[Objective]This animal experiment investigates the ameliorating effect of lithium chloride on the damage of embryonic development and hippocampal neurons in rats exposed to BaP during pregnancy,so as to provide an experimental basis for the study of its specific mechanism.[Methods]Ten-week-old pregnant SD rats were randomly divided into five groups with six rats in each group:a control group,a soybean oil group,a BaP group(20 mg·kg^(-1)BaP),a LiCl group(40 mg·kg^(-1)LiCl),and a LiCl intervention group(20 mg·kg^(-1)BaP+40 mg·kg^(-1)LiCl).From gestational day 8(GD8)to GD14,mother rats were administered by gavage once a day for continuous 7 days,and their weights were recorded every day.On GD18,fetal rats were collected from pregnant rats,and the number,weight,body length,and tail length of the pups were recorded.The morphological changes of neurons in hippocampus were observed by HE staining.The expressions of glycogen synthasc kinase-3β(GSK-3β),pGSK-3β,andβ-catenin in hippocampus were detected by Western blotting.[Results]During the experiment,the control,soybean oil,and LiCl groups showed no differences in the body weight of pregnant rats and the development indexes of fetal rats(P>0.05).On GD14 and GD18,the weights of pregnant rats in the BaP group[(323.34±5.71)g,(364.34±10.41)g]were lower than those in the control group[(339.17±7.10)g,(390.32±11.35)g](P<0.05),and the weights of pregnant rats in the LiCl intervention group[(345.05±7.72)g,(398.73±12.32)g]were higher than those in the BaP group(P<0.05).The body weight,body length,and tail length of fetal rats in the BaP group were(2.325±0.061)g,(3.072±0.077)cm,and(1.135±0.068)cm,respectively,which were lower than those in the control group[(2.563±0.091)g,(3.284±0.078)cm,and(1.276±0.041)cm](all P<0.05).The above development indexes of fetal rats in the LiCl intervention group were(2.669±0.096)g,(3.356±0.107)cm,and(1.206±0.041)cm,respectively,which were higher than those in the BaP group(P<0.05).The morphological observation results showed that neurons in dentate gyrus of hippocampus in the BaP group shrank and stained deeply,which was improved in the LiCl intervention group.The Western blotting results showed that the expression level of pGSK-3βin the BaP group was decreased(gray value ratio:0.87±0.04 in the control group,and 0.50±0.04 in the BaP group,F=19.64,P<0.001),the expression level of GSK-3βwas increased(gray value ratio:1.53±0.14 in the control group,and 2.09±0.11 in the BaP group,F=5.90,P=0.011),and the expression level ofβ-catenin was decreased(gray value ratio:1.41±0.14 in the control group,and 0.90±0.04 in the BaP group,F=11.16,P=0.001).LiCl intervention significantly reversed the decrease of pGSK-3βandβ-catenin expressions and the increase of GSK-3βexpression caused by BaP exposure(grey value for pGSK-3βwas 0.69±0.08,P=0.036;for GSK-3βwas 1.59±0.15,P=0.042;and forβ-catenin was 1.33±0.08,P=0.006).[Conclusion]LiCl intervention can improve embryonic growth retardation and hippocampal neuron damage in rats induced by BaP exposure during pregnancy.The mechanism may be related to the inhibition of GSK-3βactivity and the increase ofβ-catenin expression by LiCl.
作者
张楠
张英英
王鹤霏
陈茜
白文琳
孙谊然
张文平
ZHANG Nan;ZHANG Yingying;WANG Hefei;CHEN Xi;BAI Wenlin;SUN Yiran;ZHANG Wenping(Department of Health Toxicology,School of Public Health,Shanxi Medical University,Taiyuan,Shanxi 030000,China;Department of Epidemiology and Health Statistics,School of Public Health,Shanxi Medical University,Taiyuan,Shanxi 030000,China;Department of Child Health and Maternal and Child Health Care,School of Public Health,Shanxi Medical University,Taiyuan,Shanxi 030000,China)
出处
《环境与职业医学》
CAS
CSCD
北大核心
2021年第5期482-488,共7页
Journal of Environmental and Occupational Medicine
基金
2020年山西省研究生教育创新项目(2020SY234)
深圳市瑞普逊干细胞再生医学研究院专项研发项目(JCYJ202003010103)。
