Ha Mei, Wei Li, Guan Xie, Li Lianbing, Liu Changjiang
School of Nursing, Chongqing Medical and Pharmaceutical College, Chongqing 400020, PR China.
Key Lab of Birth Defects and Reproductive Health of National Health and Family Planning Commission, Chongqing Population and Family Planning Science and Technology Research Institute, Chongqing 400020, PR China.
Environ Pollut. 2016 Jan;208(Pt B):416-25. doi: 10.1016/j.envpol.2015.10.009. Epub 2015 Nov 6.
Di-(2-ethylhexyl) phthalate (DEHP) is used extensively in many personal care and consumer products, resulting in widespread non-occupational human exposure through multiple routes and media. DEHP has various deleterious effects including hepatotoxicity. p53 protein is a central sensor in cell apoptosis. In order to clarify the roles of p53 in DEHP-induced hepatotoxicity, Sprague-Dawley (SD) rats were dosed daily with DEHP by gavage for 30 days; BRL cells (rat liver cell line) were treated with DEHP for 24 h after pretreatment with NAC or small interfering RNA (siRNA). Results indicated that after exposure to DEHP, hepatic histological changes such as hepatocyte edema, vacuolation and hepatic sinusoidal dilation, and increased apoptosis index were observed. In the liver, DEHP induced oxidative stress and DNA damage, which activated p53 in vivo and in vitro. Pretreatment with NAC significantly reduced ROS level and p53 expression in BRL cells. The suppressed Mdm2 also contributed to p53 accumulation. Activated p53 mediated hepatocyte apoptosis via the intrinsic mitochondrial pathway, inhibiting anti-apoptotic Bcl-2 and Bcl-xL and inducing pro-apoptotic Bax, cytochrome c and caspases. In p53-silenced BRL cells, hepatocyte apoptosis mediated by p53 was attenuated. PCNA protein level was upregulated after p53 gene silencing. However, the Fas/FasL apoptotic pathway did not exhibit activated signs in DEHP-caused hepatotoxicity. Taken together, DEHP-caused oxidative stress and Mdm2 downregulation contribute to p53 activation. The p53-dependent apoptotic pathway plays critical and indispensable roles in DEHP-induced hepatotoxicity, while the Fas/FasL pathway does not involve in this molecular event.
邻苯二甲酸二（2-乙基己基）酯（DEHP）广泛用于许多个人护理和消费品中，导致通过多种途径和媒介在非职业环境下广泛接触人群。DEHP具有多种有害影响，包括肝毒性。p53蛋白是细胞凋亡的核心传感器。为了阐明p53在DEHP诱导的肝毒性中的作用，将Sprague-Dawley（SD）大鼠每天经口灌胃给予DEHP，持续30天；BRL细胞（大鼠肝细胞系）在经NAC或小干扰RNA（siRNA）预处理后，用DEHP处理24小时。结果表明，暴露于DEHP后，观察到肝脏组织学变化，如肝细胞水肿、空泡化和肝窦扩张，以及凋亡指数增加。在肝脏中，DEHP诱导氧化应激和DNA损伤，在体内和体外激活p53。用NAC预处理可显著降低BRL细胞中的ROS水平和p53表达。Mdm2的抑制也导致p53积累。激活的p53通过内在线粒体途径介导肝细胞凋亡，抑制抗凋亡的Bcl-2和Bcl-xL，并诱导促凋亡的Bax、细胞色素c和半胱天冬酶。在p53沉默的BRL细胞中，由p53介导的肝细胞凋亡减弱。p53基因沉默后，PCNA蛋白水平上调。然而，Fas/FasL凋亡途径在DEHP引起的肝毒性中未表现出激活迹象。综上所述，DEHP引起的氧化应激和Mdm2下调导致p53激活。p53依赖性凋亡途径在DEHP诱导的肝毒性中起关键且不可或缺的作用，而Fas/FasL途径不参与这一分子事件。
