Recombinant Globular Adiponectin Relieves Kidney Injury In Diabetic Mice

Objective:Changes of biochemical indicators,autophagy and endoplasmic reticulum stress indicators in diabetic mice after intervention with recombinant globular adiponectin(APN)and to investigate whether recombinant globular adiponectin can reduce kidney injury in diabetic mice by regulating autophagy and endoplasmic reticulum stress.Methods:48 male C57BL mice were randomly divided into normal control group(n=8)and diabetic model group(n=40).Model of type 1 diabetic mice was prepared by intraperitoneal injection of streptozotocin.The 24 male C57BL mice successfully modeled were randomly divided into diabetic model group(n=8),diabetic adiponectin low-dose group(n=8)and diabetic adiponectin high-dose group(n=8).Mice in the diabetic adiponectin low-dose and high-dose groups were intraperitoneally injected with adiponectin of 5 μg/kg and 15 μg/kg respectively,while mice in normal control group and diabetic model group were intraperitoneally injected with the same amount of normal saline.Blood samples were collected at the end of the 8th week of the experiment to determine the levels of blood glucose,urea nitrogen,creatinine and insulin.The animals were killed and the bilateral kidneys were quickly removed.the bilateral kidneys were washed with normal saline,drained with filter paper and weighed to calculate the weight of the kidney weight/weight(KW/W).Partial renal cortical tissues were fixed with neutral formalin solution for HE staining.The rest of the renal cortical tissue were quickly put into liquid nitrogen,frozen thoroughly and stored in the refrigerator at-70 degrees for later use.Blood glucose,urea nitrogen and creatinine were determined by biochemical method.Insulin was determined by enzyme-linked immunosorbent assay.The mRNA expression of endoplasmic reticulum stress indicators(GRP78,CHOP and caspase-12)and autophagy indicators(LC3,Beclin1 and p62)was determined by real-time quantitative PCR.Results:Compared with normal control group,the blood glucose,creatinine,urea nitrogen,kidney weight/weight levels of group B mice were significantly increased(P<0.05),insulin level was significantly reduced(P<0.05),and the pathological changes of the kidney were severe.GRP78,CHOP,caspase-12 and p62 mRNA expressions were significantly increased(P<0.05),LC3 and Beclin1 mRNA expressions were significantly reduced(P<0.05).Compared with diabetic model group,blood glucose,creatinine and urea nitrogen levels of diabetic adiponectin low-dose group mice were decreased significantly(P<0.05),renal pathological changes were reduced,GRP78,Caspase-12 and p62 mRNA expressions were decreased significantly(P<0.05),Beclin1 mRNA expression was significantly increased(P<0.05),while the renal weight/weight,insulin,the expression levels of CHOP and LC3 mRNA had no significant changes(P>0.05).Compared with diabetic model group,blood glucose,creatinine,urea nitrogen and kidney weight/weight of diabetic adiponectin high-dose group mice were significantly reduced(P<0.05),insulin level was significantly increased(P<0.05),renal pathological changes were significantly reduced,GRP78,CHOP,Caspase-12 and p62 mRNA expressions were decreased significantly(P<0.05),LC3 and Beclin1 mRNA expressions were significantly increased(P<0.05).Compared with diabetic adiponectin low-dose group mice,the blood glucose,renal weight/weight levels in diabetic adiponectin high-dose group mice were significantly reduced(P<0.05),the pathological changes of the kidney were further reduced,and the expression levels of LC3 and Beclin1 mRNA in the kidney were significantly increased(P<0.05),while the levels of creatinine,urea nitrogen,insulin,CHOP,GRP78,caspase-12 and p62 had no significant changes(P>0.05).Conclusion:After the intervention of recombinant spherical adiponectin,the blood glucose level decreased,the insulin level increased,the renal function improved,and the expression levels of autophagy and endoplasmic reticulum stress mRNA reversed in diabetic mice.Recombinant globular adiponectin may alleviate the renal injury in diabetic mice by regulating autophagy and endoplasmic reticulum stress.