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目的用谷胱甘肽(GSH)合成酶抑制剂丁硫氨酸亚甲矾胺(BSO)抑制大鼠GSH合成,探讨多药耐药相关蛋白2(MRP2)与GSH共转运体系在肝脏砷代谢过程中的作用。方法30只健康Wistar大鼠随机分为5组:第1组为对照组,给予生理盐水;第2～4组为染砷组,分别给予4、10和20 mg／kg体重的亚砷酸钠溶液,隔天染毒1次,2周后将动物处死。第5组为BSO干预组,在实验结束的前3 d,每天大鼠预先腹腔注射2 mmol／kg体重BSO溶液,4 h后再经口给予20 mg／kg体重的亚砷酸钠溶液,其他处理同上。原子吸收分光光度法测定胆汁、肝组织和全血中的总砷含量。蛋白印记法测定肝细胞膜上MRP2的含量改变。结果和对照组比较,各砷染毒组胆汁、肝脏和血砷含量均明显增高,差异有统计学意义(P<0．05);而3个染毒组间血砷差异无统计学意义(P>0．05)。随着染砷剂量增加,MRP2表达有增加的趋势,且MRP2表达量与胆汁砷的含量呈正相关(r=0．986,P<0．05)。大鼠经BSO预处理后再给予20 mg／kg体重的亚砷酸钠溶液,胆汁砷含量明显高于对照组,而低于高剂量组;肝脏和血砷水平明显高于对照组和高剂量组,差异有统计学意义(P<0．05);MPR2表达量比高剂量组减少。结论亚砷酸钠可以诱导MRP2的表达,随染砷剂量增加,MRP2表达量增加。MRP2在砷及其代谢产物的胆汁排泄过程中发挥了重要作用。MRP2转运砷及其代谢产物的作用与细胞内GSH水平相关,BSO通过抑制GSH合成,导致MRP2-GSH共转运功能减弱,砷在肝脏内蓄积增加。
OBJECTIVE: To inhibit glutathione (GSH) synthetase butanethionine-bovine serum albumin (BSO) in rat GSH synthesis and investigate the role of MRP2 and GSH cotransporter in arsenic metabolism in liver The role of the process. Methods Thirty healthy Wistar rats were randomly divided into five groups: the first group was the control group, which was given saline; the second to the fourth group were the arsenic-exposed group, which were given sodium arsenite at 4, 10 and 20 mg / kg body weight Solution, the next day exposure to 1, 2 weeks after the animals were sacrificed. Group 5 was BSO intervention group. Rats were preperitoneally injected with 2 mmol / kg body weight BSO solution 3 days before the end of the experiment. After 4 hours, 20 mg / kg body weight sodium arsenite solution was orally administered, and other Proceed as above. Determination of Total Arsenic in Bile, Liver Tissue and Whole Blood by Atomic Absorption Spectrophotometry. The content of MRP2 on the membrane of hepatocyte was detected by Western blotting. Results Compared with the control group, the contents of bile, liver and blood arsenic in all arsenic-exposed groups were significantly increased (P <0.05), while there was no significant difference in blood arsenic among the three groups P> 0.05). With the increase of arsenic dose, the expression of MRP2 tended to increase, and the expression of MRP2 was positively correlated with the content of bile arsenic (r = 0.986, P <0.05). Rats were pretreated with BSO and then given a 20 mg / kg body weight of sodium arsenite solution, arsenic content was significantly higher than the control group, but lower than the high dose group; liver and blood arsenic levels were significantly higher than the control group and high dose Group, the difference was statistically significant (P <0.05); MPR2 expression decreased compared with the high dose group. Conclusion Sodium arsenite can induce the expression of MRP2. With the increase of arsenic dose, MRP2 expression increases. MRP2 plays an important role in the bile excretion of arsenic and its metabolites. The role of MRP2 in the transport of arsenic and its metabolites is related to the intracellular GSH level. BSO inhibits the synthesis of GSH, resulting in weakened MRP2-GSH cotransport and arsenic accumulation in the liver.