砷暴露对小鼠脾脏炎症反应及Th1/Th2的影响

Effects of arsenic exposure on inflammation response and Th1/Th2 cells in spleens of mice

目的探讨慢性饮水砷暴露对小鼠脾脏的炎症反应及Th1/Th2细胞因子和转录因子表达的影响。方法将30只健康SPF级雌性昆明小鼠根据体重按照随机数字表分为对照组和25、50 mg/L NaAsO_2染毒组,每组10只。采用自由饮水方式染毒,染毒6个月后,测定小鼠脾脏组织中炎症因子IL-12和IL-6的mRNA水平。采用Real-time PCR方法分别检测脾脏Th1和Th2的转录因子T-bet、Gata3和细胞因子Ifn-γ、IL-4的mRNA表达水平。同时用Western blot法观察Nrf2、NQO1和GSTO1/2的蛋白表达水平。结果与对照组比较,随着染毒剂量的上升,各染毒组小鼠脾脏炎症因子IL-12和IL-6的mRNA水平均上升,除IL-12的25 mg/L剂量组外,差异均具有统计学意义(P<0.05);各染毒组小鼠脾脏细胞因子Ifn-γ和IL-4的转录水平呈上升趋势;Nrf2及其调控的下游蛋白NQO1和GSTO1/2的表达水平明显增加。结论慢性砷暴露小鼠免疫器官脾脏的炎症相关因子IL-12和IL-6明显增加,同时上调Th1和Th2特异性细胞因子的表达水平,调节CD4^+T淋巴细胞亚群的分化,从而发挥对小鼠脾脏的免疫调节效应。

Objective To investigate the effects of arsenic exposure by chronic drinking water on inflammatory response and function of Th1/Th2 in spleens of mice.Methods Thirty healthy SPF female Kunming mice were devided into 3 groups according to weight based on random number table:control group,25 mg/L NaAsO2 group and 50 mg/L NaAsO2 group,10 mice for each group.The mRNA levels of inflammatory cytokines IL-12 and IL-6 in spleens of mice were determined 6 months later after exposure to As by free drinking,and real-time PCR was used to detect the mRNA expression levels of Th1 and Th2 transcription factors such as T-bet,Gata3 and cytokines Ifn-γand IL-4 in spleen,meanwhile,Western blot was used to observe the protein expression levels such as Nrf2,NQO1 and GSTO1/2.Results The results showed that with the increase of dose,the mRNA levels of inflammatory cytokines such as IL-12 and IL-6 in spleens of mice increased compared with control group(P<0.05),aside from IL-12 in 25 mg/L dose group;the transcription levels of cytokines Ifn-γand IL-4 in each As-treated group also showed an upward trend,and the protein levels of Nrf2 and its regulated downstream proteins NQO1 and GSTO1/2 were significantly increased as well.Conclusion The results suggested that chronic arsenic exposure might up-regulate the inflammation related factors IL-12 and IL-6 of immune organ in mice,elevate the expression level of specific cytokines of Th1 and Th2 regulate the differentiation of CD4^+T lymphocyte subset,thereby played the immunoregulatory effect on spleen of mice.