Effect Of Copper And Nickel Combined Exposure On Apoptosis Pathway Mediated By Renal Endoplasmic Reticulum Stress In Mice

Objective:Both copper and nickel are heavy metal elements with strong biological toxicity.Numerous animal experiments have shown that the kidney is a common target.Both can be induced by endoplasmic reticulum stress and apoptosis.Between excessive disease induced cell proliferation and apoptosis,apoptosis of renal cells is an important cause of renal injury and even failure,kidney damage and even failure by ER stress mediated apoptosis pathway is a newly discovered one of the ways to induce cell apoptosis.Endoplasmic reticulum stress-mediated apoptosis is mainly mediated by caspase-12,CHOP and JNK pathways.Many stimuli can disrupt endoplasmic reticulum homeostasis.Under continuous endoplasmic reticulum stress,endoplasmic reticulum function can not be restored,and apoptosis will start.Whether Cu-Ni combined exposure causes kidney injury through the apoptosis pathway mediated by ER stress has been rarely reported,and the interaction of Cu-Ni with ER stress as the starting point is preliminary explored,providing a basis for clarifying whether Cu-Ni has antagonistic effect on the apoptosis mediated by ER stress in mouse kidney.Methods:Methods:60 six to eight weeks of male kunming mice were randomly divided into four groups,each group of 15 only.With the method of free water to virus infected cycle for 12 weeks.The control group drank distilled water,and the dosage of Cu SO₄was150ppm in the copper exposure group,300ppm NISO₄·6H₂O in the nickel exposure group,and 150ppm Cu SO₄+300ppm Ni SO₄·6H₂O in the combined exposure group.Weigh the animals once a week and observe their hair condition and mental state.After the canister,record weight of mice.The detection of the index reflects the kidney function;Using microwave digestion method and flame atomic absorption method detection of copper and nickel elements content in mice kidney;Kidney paraffin section of the line HE dyeing observation mice kidney tissue pathology change;The apoptosis of mouse kidney was observed by el staining.The protein expression levels of GRP78,ATF4,CHOP,p-JNK and Caspase-12 were detected by Western blotting.Results:1.The influence of copper and nickel combined exposure on the general condition of mice showed a time-dependent increase in the body weight of mice in each group,but the difference was not statistically significant（P>0.05）.2.Detect the content of copper,kidney and nickel in mouse kidney.3.toxic effects of copper and nickel combined exposure on renal injury;HE dyeing observation found that disordered arrangement of renal tubule in infected mice.The epithelial cells of the renal tubules are vacuolated and the glomeruli are atrophied and surrounded by inflammatory cells.Compared with the control group,the contents of serum creatinine,urinary creatinine,urinary protein and blood uric acid in infected groups were significantly increased（P<0.05）.The urea nitrogen content in all exposed groups was lower than that in control group,and the difference was not statistically significant（P>0.05）.There was no significant difference in serum creatinine,urinary creatinine,urea nitrogen and blood uric acid between Cu and Ni exposed group and Cu and Ni exposed group alone（P>0.05）.The urine protein content in Cu-Ni combined exposure group was significantly higher than that in Cu alone exposure group（P<0.01）.The results show that the effect in mice serum creatinine and urine creatinine content of copper and nickel,there is no interaction in mice blood uric acid and urine protein levels interaction exists.4.The effect of combined copper and nickel exposure on the endoplasmic reticulum stress-mediated apoptosis of mice:Tunel staining showed that the number of renal cell apoptosis in mice in each exposure group increased significantly,and the combined exposure group had the most Significantly.Compared with the control group,the protein relative expression levels of GRP78,ATF4,CHOP,p-JNK and Caspase-12 in the kidney of mice in all exposed groups were significant（P<0.05）.The relative expression levels of GRP78 and Caspase-12 were significantly increased in the Cu-Ni combined exposure group compared with the copper and nickel exposure groups alone（P<0.05）.The relative expression level of CHOP protein in Cu-Ni combined exposure group was significantly higher than that in nickel alone exposure group（P<0.01）.The relative expression levels of ATF4 and p-JNK proteins in the Cu-Ni combined exposure group were not statistically significant compared with the copper exposure group and nickel exposure group alone（P>0.05）.The result of factorial analysis showed that the combined exposure of copper and nickel had no interaction effect on the expression levels of GRP78,p-JNK,ATF4 and Caspase-12 protein,but had an interaction effect on the relative expression level of CHOP protein in mouse kidney.Conclusion:1.Combined exposure of copper and nickel leads to changes in renal function and has an antagonistic effect on uric acid,and nickel antagonizes the effect of copper on urinary protein level.2.Combined exposure of copper and nickel may activate the apoptosis pathway mediated by ER stress,and nickel antagonizes the effect of copper on the expression level of CHOP protein.