Experimental Study On Effect Of Chlorogenic Acid On Oxidative Stress Of Kidney In Diabetic Rats

Background & ObjectiveIn this day,diabetic nephropathy(DN),as a common and severe syndrome of diabetes mellitus,is one of the main causes to lead diabetes to die. Studies show that the state of oxidative stress that body of diabetes product superfluous reactive oxygen species and the antioxidantive system competence decrease play an important role in the pathogenesis of diabetes syndrome. So it becomes a natural choice using antioxidants to treat diabetes syndrome .Chlorogenic acid is an antioxidatant which is ubiquitous in vegetable kingdom. In this study, we observed the changes of oxidative stress index and other parameters of normal rats, diabetic rats and diabetic rats treated by chlorogenic acid. Then we confirm that the state of oxidative stress exist in body of diabetic rats and discuss how chlorogenic acid affect the state of oxidative and antioxidantive system.Methods:1. Grouping Thirty-six healthy female Wistar rats which weigh from 200g-250g ,are randomly averaged three groups : Contrast group (normal group,N group),diabetes mellitus group(DM group) and chlorogenic acid intervention group(CA group).2.Making diabetic rats model Streptozotocin(STZ) is dissolved into 0.1mmol/L citric acid and sodium citrate(PH4.2) buffer just before intraperitoneal injection. After 16 hours fasting,rats in DM group and CA group are injected STZ according to 60mg/kg while rats in N group are injected equal buffer.24 hours latter, using ACCU-CHEK-ACTIVE, we get the index of blood glucose of rats by cutting vena caudalis of rats. If the index is bigger than 16.7mmol/L,we regard the rat as an eligible diabetes model.3. Experiment intervention Every morning at 9:00-10:00,rat of CA group is injected 10mg chlorogenic acid by cavitas abdominalis injection and others are injected buffer as much. Every afternoon at 6:00-7:00 ,rat of DM group and CA group are hypodermic injected Insulin Zinc Protamine 2unit.Before killed,rat feed and drink freely.4. Gather specimen After 10 weeks,collet 24 hours urine of every rat,put in -80℃refrigeratory for measure urine albumin excretion rate(UAER);then measure blood glucose by cutting vena caudalis and fianlly anaesthetize rat using 10% chloral hydrate,3ml/kg,execute rats ,take out kidneys preparing for measuring the indexs.5.Measuring indexs and method blood glucose: ACCU-CHEK-ACTIVE(Roche company) ;weight of rat:ordinary balance;weight of kidneys: analytical balance; urinary albumin excretory rate:radioimmunoassay(China Institute of atomic energy) ;the activity of cortex of kidney superoxide dismutase(SOD): colorimetry ( Biotechnology Research Institute of Nanjing JianCheng) ; the activity of glutathione peroxidase(GSH-PX): hydroxylamine method (Biotechnology Research Institute of NanJing JianCheng ) ;malondialdehyde (MDA): colorimetry (Biotechnology Research Institute of NanJing JianCheng ) .6.Making Pathological section Making Pathological section hematoxylin and eosin stain.7.Statistical analysis The results were analyzed using SPSS 10.0 software wrap. The data is presented as mean±standard deviation. Statistical Comparisons were performed using ANVOA and q -test,T-test after Homogeneity-of-variance,with significance level of 0.05. Differences were considered significant when p<0.05.Result:1. Comparion of blood glucose,weight of rat and weight of kidney: Compared to those of N group ,the level blood glucose of of DM amd CA increase obviously after STZ injection,but blood glucose between DM and CA group are founded no significant difference both at the beginning and in the end. The dispersion of the weight of rat are founded significant difference, that of DM Weigh and CA is more lighter. Compared with that of CA group,the weight of rat kidney of DM group is smaller obviously and DM is bigger than N group.2.Comparion of oxidative stress index and urine albumin excretion rate: Compared with that of N group,the activity of SOD and GSH-PX of CA group and DM group reduce,the content of MDA of CA group and DM group increase, and UAER of CA group is biger. The activity of SOD and GSH-PX of CA group is improved,the content of MDA of CA group is decreased and UAER of CA group is smaller when compared to DM group.3. Pathological section result: Compared with that of N group,the kidney tissue of DM and CA group are founded congestion, CA group is obvious; Compared with that of CA group, DM section include more segmented renal glomerulus and local profuse leucocyte.Conclusion:1 The level of oxidative stress in diabetes are greatly increased.2 Chlorogenic acid is effective in improving the antioxidative ability of rat and inhibiting oxidative stress and decreasing urinary albumin.