孕期铅暴露大鼠胎盘血栓调节蛋白表达

Expression of thrombomodulin in rat placenta induced by lead exposure during different periods of gestation

目的观察孕期不同阶段铅暴露对大鼠胎盘血栓调节蛋白(thrombomodulin,TM)表达的影响,探讨铅胎盘毒性机制。方法 108只大鼠随机分为对照组与孕早、晚期和全程醋酸铅染毒组;对照组孕期饮服蒸馏水,醋酸铅染毒组于不同孕期给予0.025%醋酸铅染毒;原子吸收光谱法测定血铅;荧光定量PCR法测定TM mRNA表达;免疫组织化学方法测定TM蛋白表达。结果对照组胎盘组织中TM蛋白表达(吸光度A值)为(0.110±0.023),与对照组比较,孕早、晚期染毒组TM蛋白表达水平降低,孕全程染毒组升高,差异有统计学意义(P<0.01);孕早、晚期和全程醋酸铅染毒组TM基因mRNA表达量分别为(0.819±0.117),(0.995±0.065)和(1.213±0.128),与对照组比较差异有统计学意义(P<0.001)。结论孕期不同阶段铅暴露可影响TM蛋白和基因mRNA表达,TM表达异常可能是孕期铅暴露致胎盘损伤的重要机制之一。

Objective To explore the effect of lead exposure on mRNA and protein expression of thrombomodulin（TM） in rat placenta at various periods of gestation.Methods Totally 108 Wistar rats were divided into four groups： con-trol group and groups with lead exposure in the early,late or entire period of gestation.The lead exposure groups consumed water with 0.025% lead acetate during different gestational periods.Blood lead levels were determined with atomic absorp-tion spectrophotometry.Placental TM expression was evaluated with immunohistochemistry,and mRNA was determined with real-time polymerase chain reaction（PCR）.Results The expressions of TM protein and the expression of TM mRNA in the control group were 0.110 ± 0.023（optical density） and 1.000 ± 0.000 units,respectively.Both the expressions of TM pro-tein and mRNA in the groups with exposure of early or late lead gestation were lower than those of in the control group.Whereas the expressions in the group with lead exposure of entire gestation were higher than those of in the control group.Both values were found significantly different from those of the control group（P 0.001）.Conclusion Lead exposure dur-ing gestation affects the expression of TM in rat placenta and the expression may be the mechanism of placenta damage in-duced by lead expoure in the period of gestation.