目的 探讨姜黄素(curcumin，Cur)对砷暴露小鼠神经免疫毒性的保护效应及其可能机制。方法 80只SPF级雌性C57BL/6小鼠随机分为4组:对照组、砷处理组、Cur处理组、砷联合Cur处理组，每组20只。对照组给予蒸馏水，砷处理组给予50 mg/L NaAsO2，Cur处理组灌胃200 mg/kg Cur，时间为45 d，采用Y迷宫和水迷宫评价小鼠学习记忆能力;采用Western blot法检测小鼠海马紧密连接蛋白闭锁小带蛋白1(ZO-1)和claudin蛋白5(claudin 5)、T淋巴细胞亚群表面标志物CD4和CD8、蛋白酪氨酸激酶 2/信号转导因子和转录激活因子 3(Janus kinase 2/signal transducer and activator of transcription 3，JAK2/STAT3)通路关键分子JAK2和STAT3的蛋白表达;采用实时定量PCR检测海马1型辅助T(type 1 T helper，Th1)/Th2/Th17/调节T细胞(Treg)转录因子和细胞因子的基因表达。结果 砷处理小鼠正确指数下降，第3天和第5天逃避潜伏期延长，穿越平台次数明显降低，海马组织ZO-1、claudin 5的蛋白水平明显下降，CD4和CD8蛋白表达上升;Th1/Th17/Treg的转录因子T细胞中表达的T盒转录因子(T-bet)/维甲酸相关核孤儿受体γt(RORγt)/叉头状转录因子P3(FOXP3)mRNA表达下降;Th1和Th17的细胞因子γ干扰素(IFN-γ)和白细胞介素17(IL-17)的mRNA明显下降，而Th2的转录因子GATA结合蛋白3(GATA3)和细胞因子IL-4的mRNA水平明显增加;此外，JAK2和STAT3的磷酸化水平增加。与砷单纯处理组相比，砷联合Cur处理组小鼠正确指数明显上升、第3天至第5天逃避潜伏期时间均缩短，穿越平台次数增加，海马组织ZO-1和claudin 5蛋白水平增加，CD4和CD8蛋白水平下降，Th2的转录因子GATA3和细胞因子IL-4的mRNA水平减少，Th17的转录因子RORγt和细胞因子IL-17 mRNA水平上升;JAK2和STAT3的磷酸化水平下降。结论 Cur可能通过抑制JAK2/STAT3信号通路，进而改善砷引起的小鼠学习记忆能力下降，逆转砷暴露小鼠固有免疫组分血脑屏障通透性的破坏，以及拮抗砷所致的海马组织中CD4和CD8分子变化及CD4+T淋巴细胞亚群Th1/Th2/Th17/Treg失衡，最终拮抗砷诱导的神经毒性。
Curcumin prevents the arsenic-induced neuroimmune injury through JAK2/STAT3 pathway
Objective To investigate the protective effect of curcumin(Cur)against arsenic-induced neuroimmune toxicity and the underlying molecular mechanisms in vivo.Methods Eighty SPF female C57BL/6 mice were randomly assigned to four groups:a control group,an arsenic-treated group,a Cur-treated group and an arsenic+Cur group,with 20 mice in each group.The control group received distilled water;the arsenic-treated group was given 50 mg/L NaAsO2 in the drinking water;the Cur-treated group was gavaged with 200 mg/kg of curcumin for 45 days;and the arsenic+Cur group received distilled water and was gavaged with 200 mg/kg of curcumin.Y-maze and Morris water maze experiments were conducted to assess the learning and memory ability of the mice.Western blot analysis was used to detect protein levels of blood-brain barrier tight junction proteins zonula occludens protein 1(ZO-1)and claudin 5,T lymphocyte subpopulation CD4 and CD8,Janus kinase 2/signal transducer and activator of transcription 3(JAK2/STAT3)signaling pathway-related molecules JAK2 and STAT3.Real-time PCR was used to assess the mRNA levels of CD4+T lymphocyte subsets type 1 T helper(Th1),Th2,Th17 and regulatory T cells(Treg)transcription factors and cytokines in hippocampus.Results Compared with the control group,the arsenic-treated group showed a significantly decreased correct rate,increased latency to reach the platform on the third and fifth days,and reduced times of crossing the platform.The expression of ZO-1 and claudin 5 protein decreased significantly,and the protein levels of CD4 and CD8 were up-regulated.The mRNA levels of Th1,Th17,and Treg transcription factor T-box expressed in T cell(T-bet),retinoid-related orphan receptor gamma t(RORγt),and forkhead box protein 3(FOXP3)in the arsenic-treated group were decreased.Th1 and Th17 cytokines interferon γ(IFN-γ)and interleukin 17(IL-17)were markedly decreased.In contrast,the mRNA levels of the Th2 transcription factor GATA binding protein 3(GATA3)and cytokine IL-4 in arsenic-treated group were higher than those in the control group.Furthermore,the protein levels of phosphorylated JAK2(p-JAK2)and phosphorylated STAT3(p-STAT3)increased.Compared with the arsenic-treated group,the arsenic+Cur group demonstrated a significantly increased correct rate,decreased latency to reach the platform on the third and fifth days,and increased times of crossing the platform.The protein expression levels of ZO-1 and claudin 5 increased significantly,and the protein levels of CD4 and CD8 were down-regulated.The mRNA levels of Th2 transcription factor GATA3 and cytokine IL-4 were decreased.The mRNA levels of Th17 transcription factor RORyt and cytokine IL-17 were markedly increased.Furthermore,the protein levels of p-JAK2 and p-STAT3 decreased.Conclusion Through inhibiting the JAK2/STAT3 signaling pathway,curcumin could improve arsenic-induced decline in learning and memory abilities in mice,reverse the destruction of blood-brain barrier permeability of innate immune system components in arsenic-exposed mice,and antagonize arsenic-induced increase in the number of renal CD4 and CD8 molecule as well as the imbalance of CD4+T lymphocyte subsets(Th1,Th2,Th17 and Treg),ultimately counteracting arsenic-induced neurotoxicity.
万方数据
维普
