DEHP与DBP联合染毒对雌性大鼠糖代谢的影响

Effects of Combined Exposure of DEHP and DBP on Glucose Metabolism in Female Rats

目的探讨邻苯二甲酸二(2-乙基己基)酯(di-2-ethylhexyl phthalate,DEHP)和邻苯二甲酸二丁酯(di-n-butyl phthalate,DBP)暴露对雌性大鼠血清胰岛素水平、氧化应激和胰腺组织中凋亡蛋白的影响。方法将40只SD雌性大鼠随机分为4组,每组10只,分别设置为对照组、DEHP染毒组(1/40 LD50,750 mg·kg^(-1))、DBP染毒组(1/40 LD50,500 mg·kg^(-1))和DEHP+DBP(750+500)mg·kg^(-1)染毒组(联合染毒组),染毒8周末测定空腹血糖值,心尖取血处死,取胰腺组织称量后计算器官系数。测定血清中的胰岛素浓度并计算胰岛素抵抗指数(HOMA-IR)、胰岛素敏感指数(ISI);测定血清中的氧化损伤指标[超氧化物歧化酶(SOD)活力、丙二醛(MDA)含量]。蛋白免疫印记(Western blot)法检测Caspase 3、Caspase 9、Bax、Bcl-2含量的变化。结果与对照组相比,DEHP、DBP单独染毒及联合染毒雌性大鼠体质量增长、胰腺重量和器官系数、末次空腹血糖值的差异均无统计学意义(P均>0.05);联合染毒组可使血清胰岛素浓度升高、HOMA-IR增加、ISI降低(P均<0.05);DEHP、DBP单独染毒以及联合染毒可使SOD活力下降、MDA含量升高,Bax、Caspase 9、Caspase 3蛋白表达增加、Bcl-2蛋白表达下降、Bcl-2/Bax比值下降(P均<0.05)。结论DEHP和DBP联合染毒可导致雌性大鼠糖代谢紊乱;该过程可能通过氧化-抗氧化系统的平衡被破坏从而激活细胞线粒体凋亡通路相关蛋白的表达,诱导胰岛β细胞发生凋亡。

Objective To explore the effects of di-2-ethylhexyl phthalate(DEHP)and di-n-butyl phthalate(DBP)exposure on serum insulin levels in female rats,Oxidative stress and the influence of apoptotic proteins in pancreatic tissue.Methods A total of 40 SD female rats were randomly divided into 4 groups,with 10 rats in each group,and they were set as the control group,DEHP-exposed group(1/40 LD_(50),750 mg·kg^(-1)),and DBP-exposed group(1/40 LD_(50),500 mg·kg^(-1)),and DEHP+DBP(750+500)mg·kg^(-1)exposure group.The fasting blood glucose level was measured at the end of the 8th week of exposure,blood was taken from the apex of the heart and sacrificed,and the pancreatic tissue was weighed and the organ coefficient was calculated.The concentration of insulin in the serum was measured and the insulin resistance index(HOMA-IR)and insulin sensitivity index(ISI)was calculated.The oxidative damage indicators[superoxide dismutase(SOD)activity,malondialdehyde(MDA)content]in the serum was determined.Western blot method was used to detect the changes of Caspase 3,Caspase 9,Bax and Bcl-2 levels.Results Compared with the control group,there were no statistically significant differences in weight gain,pancreatic weight and organ coefficients,and last fasting blood glucose in female rats exposed to DEHP and DBP alone or in combination(P all>0.05).The combined exposure group could increase serum insulin concentration and HOMA-IR,decrease ISI,and the difference is statistically significant(P all<0.05).DEHP and DBP alone and combined exposure can decrease SOD activity and increase MDA content.Bax,Caspase 9,Caspase 3 protein expression increased,and Bcl-2 protein expression decreased.Bcl-2/Bax ratio decreased,and the difference was statistically significant(P all<0.05).Conclusion Combined exposure of DEHP and DBP can lead to disorder of glucose metabolism in female rats.This process may be disrupted by the balance of oxidation-antioxidant system to activate the expression of mitochondrial apoptosis pathway-related proteins and induce pancreaticβcells apoptosis occurs.