基于Nrf2信号通路探讨PFOA/PFOS致肝毒性损伤的机制及柚皮苷干预作用的研究

Perfluorooctanoic acid (PFOA)/perfluorooctane sulfonate (PFOS) exposure may cause hepatotoxic damage. Our previous study found that PFOA/PFOS exposure inhibited Nrf2 expression and induced oxidative stress and apoptosis in the hepatic tissue. However, the up-regulation the expression of Nrf2 and its target genes attenuated PFOA-induced hepatotoxicity. Therefore, we speculate that the activation of Nrf2 signaling pathway can protect against PFOA/PFOS-induced hepatotoxicity. In this study, the hepatotoxicity induced by PFOA/PFOS will be evaluated at organ, cell and molecular levels, and its relationship to hepatic cell apoptosis and autophagy will be analyzed by detecting the expression of apoptosis- and autophagy-related genes. Furthermore, the activation and inhibition of Nrf2 signaling pathway will be induced to investigate the regulatory effect of Nrf2 signaling pathway on PFOA/PFOS-caused hepatocyte apoptosis and autophagy dysfunction. Moreover, the expression of Nrf2 and its target genes and the nuclear translocation of Nrf2 will be determined to reveal whether the protective effect of naringin on PFOA/PFOS-induced hepatic injury is involved in the activation of Nrf2 pathway. These studies will provide a new target and an antioxidant intervention strategy of biologically active natural substances for the prevention and treatment of hepatotoxic damage caused by perfluorinated compounds.

全氟辛酸(PFOA)/全氟辛烷磺酸(PFOS)可导致肝毒性损伤。Nrf2在调节应激反应中起关键作用。我们前期实验发现PFOA/PFOS抑制了小鼠肝Nrf2表达，导致肝组织氧化应激和凋亡，而上调Nrf2及其靶基因表达可缓解PFOA诱导的肝毒性。据此，我们推测“激活Nrf2信号通路对PFOA/PFOS诱导的肝损伤起保护作用”。本项目拟在器官、细胞及分子水平探讨PFOA/PFOS致肝毒性的作用机制，通过检测细胞凋亡和自噬相关基因的表达阐明PFOA/PFOS诱导的肝毒性与细胞凋亡和自噬的相关性，重点关注Nrf2信号通路的激活和抑制对PFOA/PFOS诱导的肝细胞凋亡和自噬异常的调控作用，并通过测定Nrf2及其下游靶基因表达和Nrf2核转位情况探讨柚皮苷对PFOA/PFOS致肝损伤的保护机制，是否与Nrf2信号通路的激活有关。为防治全氟化合物引起的肝毒性损伤提供新的靶点和天然抗氧化物干预的新策略。

环境污染物全氟辛酸(PFOA)/全氟辛烷磺酸(PFOS)暴露可导致肝毒性损伤。Nrf2在调节应激反应中起关键作用。本项目主要探讨了柚皮苷(Nar)通过调控Nrf2信号通路对PFOA/PFOS引起的肝损伤的保护作用。结果表明，PFOA和PFOS显著下调了Nrf2及其下游抗氧化酶SOD和CAT的表达和活性，增加了细胞膜脂质过氧化产物MDA和H2O2的产生，并上调了促凋亡蛋白p53和Bax的表达以及炎症因子TNF-α、CRP和IL-6的表达，表明PFOA/PFOS可通过抑制Nrf2信号通路诱导氧化应激、炎症反应和细胞凋亡，从而导致肝毒性损伤。而Nrf2信号通路的天然激活剂Que显著缓解了PFOA/PFOS诱导的肝损伤。和单独PFOA/PFOS处理组相比，Que降低了血清ALT和AST水平以及肝脏MDA、CRP和IL-6的生成，增加了SOD和GSH的含量，并抑制了肝细胞凋亡。此外，GSPE也通过上调Nrf2的表达抑制了PFOA/PFOS诱导的氧化应激、炎症反应和凋亡。这些结果表明Nrf2信号通路的激活能够缓解PFOA/PFOS暴露导致的肝损伤。Nar具有抗氧化、抗炎等多种生物学活性和药理学作用。因此，我们研究了Nar对PFOA/PFOS诱导的肝毒性的保护作用及其机制。结果表明，Nar可以通过增加以Nrf2为核心的抗氧化防御体系抑制氧化应激、炎症反应和细胞凋亡，从而保护PFOA/PFOS诱导的肝损伤。我们的研究结果可为预防和治疗全氟化合物导致的肝毒性损伤供理论基础。