母鼠孕晚期铅暴露致后代幼鼠牙胚中Cbfα 1基因的表达

The Cbfα1 gene expression on the teeth of rat offspring of lead exposure in late-gestation

目的观察母鼠怀孕晚期铅暴露后幼鼠牙胚Cbfα1的表达变化。方法 30只受孕母鼠随机分成3组(每组10只),即对照组、孕晚期低剂量组60mg/kg组和孕晚期高剂量组240mg/kg组。各组饮用去离子水,而实验组自怀孕14d后改用含Pb2+去离子水。在幼鼠生后第2d,4d,8d,20d将幼鼠脱椎处死,分离解剖含下颌第一磨牙区的下颌骨,4%多聚甲醛固定过夜,梯度脱水,石蜡包埋,近远中向5μm连续切片,常规HE染色,Power VisionTM二步法进行免疫组化制片,观察牙胚发育情况。结果病理组织学可见随着母乳铅暴露剂量的增加,后代牙胚釉质层变薄,甚至消失。免疫组化结果发现正常组阳性细胞沿着牙槽骨边缘表达强烈,计数5个视野下阳性细胞数为458.12±14.26,牙周膜中心很少分布,而实验各组随着暴露时间和剂量的增加,最初的牙槽骨和牙周膜的表达与相应对照组比较显著受到抑制,阳性表达细胞数明显下降,计数5个视野下阳性细胞数孕晚期低剂量组为67.12±9.15,孕晚期高剂量组为53.12±11.19,与对照组比较差异均具有极显著性意义(P<0.001)。结论母鼠孕晚期铅暴露致后代牙胚中Cbfα1基因的表达受到明显影响。

Objective To investigate the Cbfα1gene expression in the dentary germ of rat offspring due to lead exposure in late-gestation.Methods A toal of 30 pregnant SD rats were divided into three groups randomly：high level lead group（240mg/kg）,low level lead group（60mg/kg） and control group with ten rats in each group.The three groups from the 14d after gestation to the end of the gestation were given either deionized water in control group or deionized water containing Pb2＋ as lead.After birth 2d,4d,8d,20d,the rat offspring were killed by pulling the neck,and their bilateral mandibular under first molar with surrounding alveolar bone were taken out,then the tissues were fixed with 4% paraformaldehyde at 4℃ over night,dehydrated,embedded in paraffin and serially sectioned at 5μm.Immunohistochemical assay was adoped to determine the tissue distribution and cellular localization of Cbfα1.Results Pathological histology analysis showd adamantine layer thinning even disappearance with the lead exposure in the test group.Immunohistochemical assay showed that the control group Cbfα1 gene expression was stronger than experimental group which expressed along the alveolar edge.Count the number of positive cells in five fields was 458.12 ± 14.26 in control group and in two experimental group was 67.12±9.15,53.12±11.19（P0.001） respective.Conclution The Cbfα1 gene expression is obviously inhibition in the dentary germ of rat offspring due to lead exposure in lategestation.