Expression And Role Of MiRNA-155 In Diabetes Mice

Diabetic kidney disease(DKD)is one of the serious microvascular complications of diabetes.In recent years,the incidence of DKD has gradually increased worldwide.As of 2017,there were 425 million adult diabetic patients worldwide,and approximately 25%-40% of diabetic patients in China will eventually develop diabetic nephropathy.Because of the huge social and economic burden of diabetic nephropathy,its diagnosis and management are of great significance in clinical and society.At the current stage,although the progress of diabetic nephropathy has been effectively delayed by optimizing hypoglycemic and antihypertensive,and rationally applying comprehensive diagnosis and treatment methods such as ACEI and ABR,it still cannot effectively reduce the new incidence of ESRD.Due to the mixed occurrence of various complications,it is more difficult to treat end-stage renal disease caused by diabetic nephropathy compared with other kidney diseases.However,the pathogenesis of diabetic nephropathy has not been known so far.To further reveal the pathogenesis of diabetic nephropathy and find new DKD treatment targets are the current research hotspots.MicroRNA is a type of non-coding RNA of about 22 nt.It can bind to the 3 ?non-coding region(3?UTR)of the target gene,induce its degradation or inhibit its translation,and play an important role in various physiological and pathological processes.In the kidney,miRNAs are involved in water homeostasis,osmoregulation,renin production,processing of proximal tubule sodium and potassium,calcium induction,and kidney development and even aging.In recent years,studies related to the pathogenesis of DKD have found that miRNAs can participate in diabetic kidney injury by regulating the expression of related genes such as inflammation,fibrosis,extracellular matrix deposition and oxidative stress,affecting the occurrence and prognosis of DKD.MicroRNA is closely related to the occurrence and development of DKD,and can be used as a new potential biomarker for early diagnosis,disease monitoring and treatment of DKD.In our previous studies,we found that miR-155 expression in serum of patients with diabetic kidney disease was reduced;its expression was positively correlated with the eGFR process and negatively correlatedwith urinary protein excretion.Many studies have also found that miRNA expression levels in serum,urine,and kidney tissue of patients with diabetic nephropathy are abnormal,so we believe that miR-155 may be related to the onset of diabetic kidney disease.Objective: To investigate the expression of miR-155 in serum and kidney tissue of db / db type 2 diabetic mice and STZ-modeled type 1 diabetic mice,and the role of miR-155 in the development of diabetic nephropathy.Research objects and methods: In this paper,db / db mice and STZ-modeled type1 diabetic mice were used as the research objects,and C57 mice were used as the control group.In this study,4-week-old male C57 / BL mice were induced by intraperitoneal injection of STZ(60mg / kg)for three consecutive days to induce a T1 DM animal model.Random blood glucose was measured three days after normal diet feeding,and random blood glucose> 180 mg / dL(16.7mmol / L)mice were used as the STZ model group.Mice in each group were randomly divided into 6,8,and10-week-old groups with increasing age.Real-time qPCR was used to determine the expression of miR-155 in serum and kidney tissues of mice in 6,8 and 10-week-old groups.Histochemical,real-time qPCR and western-blot were used to determine the expression levels of Ets-1,eNOS,AGTR1 mRNA and protein in mouse kidney tissue.Results: 1.Compared with the control group,the expression of miRNA-155 in serum of db / db and STZ model mice at 6,8 and 10 weeks of age were all increased(P<0.05),and the up-regulation was most pronounced at 10 weeks of age(P<0.01),followed by 8 weeks of age and 6 weeks of age.2.Compared with the control group,the expression of miRNA-155 in the kidney tissues of db / db and STZ model mice at 6,8 and 10 weeks of age were all increased(P<0.05),and the increase was most pronounced at 10 weeks of age(P<0.01),followed by 8 weeks and 6 weeks.3.Compared with the control group,the expressions of Ets-1,eNOS and AGTR1 mRNA in the kidney tissue of db / db and STZ model mice at 6,8 and 10 weeks of age were all reduced(P<0.05),and the down-regulation was most significant at 10 weeks of age.Significant(P< 0.01),followed by 8 weeks of age and6 weeks of age.4.Immunohistochemistry revealed that Ets-1,eNOS and AGTR1 were localized in glomerular endothelial cells in mice.5.Compared with the control group,there was no significant change in Ets-1,eNOS and AGTR1 in the kidney tissue of 6-week-old db / db mice;the expression level of eNOS protein in the kidney of 8-week-old db / db mice was down-regulated(P<0.05);10 The expression level of AGTR1 protein decreased at week age(P<0.05),and the expression levels of Ets-1 and eNOS protein were significantly decreased(P<0.01).Compared with the control group,the expression of eNOS in kidney tissue of 6-week-old STZ model mice was down-regulated(P<0.05),and Ets-1 and AGTR1 were not significantly changed.AGTR1 protein expression level was significantly down-regulated(P<0.01).Conclusion: The expression level of miRNA-155 in serum and kidney tissues of db / db and STZ model mice gradually increased with the progress of DKD,while the mRNA and protein of miR-155 target Ets-1,eNOS and AGTR1 The expression level gradually decreases with the progress of diabetic kidney disease.This result suggests that miRNA-155 may participate in the occurrence and development of diabetic nephropathy by inhibiting its target genes Ets-1,eNOS and AGTR1,affecting endothelial cell function.