二氧化钛纳米颗粒的肝细胞毒性及分子机制研究

Study on hepatotoxicity and molecular mechanism of titanium dioxide nanoparticles

研究二氧化钛纳米颗粒(TiO2)的肝细胞毒性及分子机制。将120只健康成年ICR小鼠分为空白组、TiO2低、中、高剂量组4组,TiO2组每天分别经尾静脉注射10、50、150 mg/kg的TiO2,空白组给予生理盐水。连续注射2 w后,称量小鼠体重、肝重,计算肝系数;检测血清ALT、AST、ALP、LDH水平,检测肝组织抗氧化酶SOD、CAT、APx、GSHPx活性,ELISA法检测血清IL-6、IL-10、TNF-α、CRP的含量,Western blot检测肝组织PD-1、PD-L1蛋白表达水平。空白组肝系数、ALT、AST、ALP、LDH、IL-6、IL-10、TNF-α、CRP水平均显著低于TiO2组,SOD、CAT、APx、GSHPx水平均显著高于TiO2组(P<0.05);各TiO2组中,TiO2剂量越大,肝系数、ALT、AST、ALP、LDH、IL-6、IL-10、TNF-α、CRP越高,而SOD、CAT、APx、GSHPx活性越低;与空白组相比,TiO2呈剂量依赖性促进PD-1、PDvL1蛋白表达(P<0.05)。TiO2可能通过PD-1/PD-L通路对小鼠肝细胞产生毒性作用,且具有一定的剂量效应依赖关系。

Objective To study the hepatotoxicity and molecular mechanism of titanium dioxide nanoparticles(TiO2).Methods A total of 120 healthy adult ICR mice were divided into a blank group and three TiO2 groups(low,medium and high dose,respectively).On a daily basis,the TiO2 groups were injected with 10,50 and 150 mg/kg TiO2 via caudal vein respectively,and the blank group was injected with normal saline.After two weeks of injection,the body weight and liver weight were measured and the liver coefficient was calculated;levels of serums ALT,AST,ALP and LDH were determined,the activities of antioxidant enzymes SOD,CAT,APx and GSHPx in liver tissues were tested,the contents of serum IL-6,IL-10,TNF-a and CRP were detected by ELISA method,and the expressions of proteins PD-1 and PD-L1 in liver tissues were detected by Western blot.Results The liver coefficient,levels of ALT,AST,ALP and LDH,and contents of IL-6,IL-10,TNF-a and CRP in the blank group were significantly lower than that in the TiO2 groups,and the activities of antioxidant enzymes SOD,CAT,APx and GSHPx were significantly higher than that in the TiO2 groups(P<0.05);among the three TiO2 groups,the liver coefficient,levels of ALT,AST,ALP and LDH,and contents of IL-6,IL-10,TNF-a and CRP increased with the dose of TiO2,while the activities of SOD,CAT,APx and GSHPx decreased with the dose;compared with the blank group,the TiO2 promoted the expressions of proteins PD-1 and PD-L1 in a dose-dependent manner(P<0.05).Conclusion TiO2 may have a toxic effect on the mice liver hepatocytes via PD-l/PD-L pathway in a certain dose-dependent manner.