Research On Effects And Mechanisms Of Ginsenoside Rg3 On Diabetic Kidney Disease In Mice By Regulating PPARγ

Due to the increasing aging of the world’s population,the change of people’s lifestyle and diet and the influence of metabolic syndrome and other factors,the prevalence of diabetes mellitus(DM)around the world is increasing year by year.Kidney is an important target of microvascular injury in DM,and Diabetic Kidney Disease(DKD)is one of the most serious complications of DM.DKD not only seriously affects patients’ daily life,but also brings great economic burden to patients and their families.At present,there is no specific prevention and treatment of DKD,and the main treatment methods are lifestyle intervention,blood pressure control and blood sugar control.Therefore,it is very important to explore new therapeutic methods for the early prevention and treatment of DKD.Thiazolidinediones(TZDs) are important hypoglycemic drugs,which can be used for early prevention and treatment of DKD.They are also the only insulin sensitizers specifically used to treat insulin resistance.proliferator-activated receptors gamma(PPARγ)is regulated by proliferator-activated receptors.Although TZDs has the advantages of reducing insulin resistance,increasing insulin utilization,protecting pancreatic β cells,delaying the development of DKD,etc.,serious side effects caused by TZDs,such as weight gain,fluid retention,edema,arrhythmia and heart failure,make TZDs gradually withdrawn from first-line use.Therefore,we hope to explore drugs with similar mechanisms that can be used to prevent and treat DKD.Ginsenoside Rg3(Rg3)is one of the main active components of red ginseng.It has many pharmacological functions,such as immune regulation,anti-inflammatory,inhibition of tumor cell proliferation,promotion of tumor cell apoptosis,etc.,and has been developed as the adjuvant anti-tumor Shenyi capsule.In addition,Rg3 also has a certain improvement effect on various tissue and organ damage caused by metabolic diseases such as hypertension,hyperglycemia and hyperlipidemia.Rg3 has been shown to alleviate ox-LDL(Low Density Lipoprotein)-induced endothelial dysfunction and prevent atherosclerosis in Apo E-/-mice by modulating PPAR gamma.Rg3 also reduces early liver damage by inhibiting inflammation and fibrosis,which is also associated with regulation of PPARγ.Therefore,we speculate that Rg3 may play a protective role against DKD by regulating PPARγ.1.Protective effect of ginsenoside Rg3 on DKD in miceWild Type(WT)mice and db/db mice were randomly divided into 2 groups with8 mice in each group,namely,WT group,WT+Rg3 group,db/db group,db/db+Rg3group.Mice in WT+Rg3 and db/db+Rg3 groups were given 30 mg/kg Rg3 by gavage,and the other groups were given the same volume of 0.5% Carboxymethylcellulose sodium(CMC-Na).After 8 weeks of intragastric administration,body weight,blood glucose,blood lipid and renal function of mice in each group were detected.The kidney tissues of mice were selected for renal histological examination,the protein expression levels of TGF-β1 and PPARγ were detected by immunohistochemistry,and the mRNA levels of TNF-α,IL-6,Col-Ⅰ and Col-Ⅲ were detected by q PCR.The expression levels of PPARγ,Col-Ⅰ,Col-Ⅲ and p-NF-κB p65 in renal tissues were determined by western blot.The results showed that Rg3 had no significant effect on kidney morphology and function in WT mice,and could alleviate kidney morphology and function damage in db/db mice,but had no significant effect on body weight,blood glucose and blood lipid in mice.Rg3 down-regulates mRNA and protein expression levels related to inflammation and fibrosis in kidney tissue of db/db mice,and up-regulates PPARγ expression.2.Protective effect and mechanism of ginsenoside Rg3 against SV40 damage induced by high glucoseWe used 80 mmol/L High glucose(GLU)to establish mouse mesangial cells(SV40 MES 13(SV40)model of high glucose damage,and screened out the optimal concentration of Rg3 to study the protective effect of 30 μmol/L.To verify whether the anti-inflammatory,antifibrotic and PPARγ regulation effects of Rg3 in this model are consistent with animal experiments,cell experiments were conducted in four groups: control group,Rg3 group,GLU group,and GLU+Rg3 group.MRNA levels of TNF-α,IL-6,Col-Ⅰ and Col-Ⅲ were detected by q PCR,and protein expression levels of PPARγ,Col-Ⅰ and Col-Ⅲ were detected by western blot.The results showed that Rg3 significantly increased the expression of SV40 PPARγ after GLU injury,and inhibited the expression of inflammatory cytokines and fibrosis-related proteins.These results indicated that Rg3 had a significant protective effect on SV40 damage induced by GLU.The experimental groups were GLU group,GLU+Rg3 group,GLU+GW group,GLU+Rg3+GW group.mRNA levels of TNF-α,IL-6,Col-Ⅰ and Col-Ⅲ were detected by q PCR,and protein expression levels of PPARγ,Col-Ⅰ and Col-Ⅲ were detected by western blot.The results showed that GW9662 could significantly inhibit the expression of PPARγ,and antagonize the down-regulation effect of Rg3 on SV40 inflammatory factor and fibrosis factor in GLU injury.It is suggested that Rg3 reduces SV40 damage induced by GLU and is associated with upregulation of PPARγ.3.Protective effect of PPARγ-based ginsenoside Rg3 on DKD in miceWT mice and db/db mice were randomly divided into 2 and 4 groups,namely,WT group,WT+GW group,db/db group,db/db+Rg3 group,db/db+GW group,db/db+Rg3+GW group,with 8 mice in each group.db/db+Rg3 group was given 30mg/kg Rg3 by gavage every day,WT+GW group and db/db+GW group were given GW9662 5mg/kg by gavage every day,db/db+Rg3+GW group was given 30 mg/kg Rg3 and GW9662 5mg/kg by gavage every day.WT and db/db groups were given0.5% CMC-Na of the same volume by gavage every day.After 8 weeks of administration,body weight,blood glucose,blood lipid and kidney function were detected.The mouse kidneys were taken for renal histopathological examination,the protein expression levels of TGF-β1 and PPARγ were detected by immunohistochemistry,and the mRNA levels of TNF-α,IL-6,Col-Ⅰ and Col-Ⅲ were detected by q PCR.The expression levels of PPARγ,Col-Ⅰ,Col-Ⅲ and p-NF-κB p65 in renal tissues were determined by western blot.The results showed that GW9662 had no significant effect on kidney morphology and function in WT mice,and could antagonize the improvement effect of Rg3 on kidney morphology and function injury in db/db mice.GW9662 antagonized the effect of Rg3 on up-regulating PPARγexpression and down-regulating mRNA and protein expression levels related to inflammation and fibrosis in kidney tissue of db/db mice.It is suggested that the protective effect of Rg3 on kidney injury in db/db mice may be realized through upregulation of PPARγ.In conclusion,this study confirmed that ginsenoside Rg3 can reduce SV40 damage induced by high glucose,kidney inflammation and fibrosis in db/db mice,and protect DKD in mice,and its mechanism is related to up-regulation of PPARγ.