| Objective: Gestational diabetes mellitus(GDM)refers to diabetes mellitus which occurs during pregnancy only,and normal glucose metabolism before pregnancy.With the improvement of living standards and dietary changes,the incidence of GDM has been increasing globally year by year.GDM has adverse effects on both mothers and children,such as: macrosomia,postpartum hemorrhage,shoulder dystocia,spontaneous abortion,preeclampsia,fetal malformation,neonatal encephalopathy,neonatal hyperbilirubinemia,neonatal hypoglycemia,etc.GDM also increases the risk of maternal type 2 diabetes,cardiovascular disease and the risk of neonatal long-term obesity.Most GDM patients can control their blood glucose within a satisfactory range through reasonable diet control and proper exercise treatment.However,for patients with GDM who are not satisfied with blood glucose control,the only drug currently in our GDM treatment guidelines is insulin.Because insulin needs to be injected subcutaneously,GDM patients have poor compliance and are difficult to manage.Metformin is currently an effective oral drug for the treatment of type 2 diabetes mellitus,and its safety and effectiveness in the application in patients with GDM have been continuously confirmed.However,metformin for the treatment of GDM has not been included in the treatment guidelines for GDM,and there is still a lack of relevant basic research inChina.The purpose of this study was to investigate the effect and possible mechanism of metformin on pregnant and middle-aged kidneys of GDM mice with gestational diabetes mellitus through the GDM model established by yu xinyang of my experimental team.Methods :(1)The GDM model of C57 mice was induced by high-fat diet.The weight of pregnant mice,oral glucose tolerance test,fasting blood glucose,HOMA-IR and so on were measured to determine whether the GDM mouse model was successfully developed.(2)The GDM treatment group was given metformin at different concentrations(300,600 mg·kg 1·d-1)at E11.5d to E17.5d for intervention.OGTT was performed on E16.5d in all pregnant mice to detect the glucose tolerance level.Urine samples were taken on E17.5d for the determination of urinary microprotein,and the level of renal dysfunction was detected.Blood samples were taken on E18.5d to measure fasting blood glucose,fasting insulin and HOMA-IR.Serum ?2-microglobulin was determined to detect the level of renal dysfunction.The pathological changes of the kidney were observed by HE staining and PAS staining.The serum inflammatory cytokines IL-6 and TNF-? were determined.The correlation between serum inflammatory cytokines(IL-6,TNF-?)and the renal dysfunction indicators(urinary microprotein,serum ?2-microglobulin)was detected to investigate whether IL-6 and TNF-? were related to the protective effect of metformin on the kidney of GDM mice during pregnancy.Western blotting was used to detect the expression of Extracellular regulated protein kinases(ERK),c-jun n-terminal kinase(JNK)and P38 of the Mitogen activated protein kinase(MAPK)family to investigate whether the MAPK pathway is related to the protective effect of metformin on the kidney of GDM mice during pregnancy.(3)The GDM treatment group was given 600 mg·kg 1·d-1 metformin for intervention at E11.5d-E17.5d.Maintenance feed wasgiven until 26 weeks of age after delivery.OGTT was used to detect the glucose tolerance level.Urine samples were taken to measure urinary microprotein and the level of renal dysfunction.Blood samples were taken to measure fasting blood glucose,fasting insulin and HOMA-IR.Serum?2-microglobulin was determined to detect the level of renal dysfunction.The pathological changes of the kidney were observed by HE staining and PAS staining.Serum inflammatory cytokines of IL-6 and TNF-? were determined to determine whether IL-6 and TNF-? were related to the protective effect of metformin treatment during pregnancy on the kidney of mice in middle age with the history of GDM.Western blotting was used to detect the expressions of ERK,JNK and P38 in the kidney of the MAPK family,and to detect whether the MAPK pathway was related to the protective effect of metformin treatment during pregnancy on the kidney of mice in middle age with the history of GDM.Results :(1)The GDM model of C57 mice induced by HFD showed increased weight,increased blood glucose at all time points of OGTT,increased AUC,and increased HOMA-IR.(2)The protective effect of metformin on the kidney of GDM mice during pregnancy.The mice in the GDM group showed significant weight gain,abnormal glucose tolerance and insulin resistance.Urinary microprotein and ?2-microglobulin in the GDM group were significantly increased.In the GDM group,HE staining of kidney showed increased glomerular volume and PAS staining showed basement membrane thickening and interstitial hyperplasia.Inflammatory cytokines of IL-6 and TNF-? in serum in the GDM group were significantly increased.The protein expressions of p-ERK,p-P38 and p-JNK in the GDM group were significantly increased.The GDM mice treated with metformin showed significantly decreased body weight,abnormal glucose tolerance,insulin resistance,urinary microprotein andserum ?2-microglobulin.The pathology of GDM mice treated with metformin showed decreased glomerular volume(HE staining)and renal basement membrane thickness(PAS staining).In the metformin treatment group,inflammatory cytokines of IL-6 and TNF-? in serum were significantly decreased.The protein expressions of p-ERK,p-P38 and p-JNK in the metformin treatment group decreased significantly.(3)The protective effect of metformin treatment during pregnancy on the kidney of middle-aged mice with the history of GDM.weight gain,abnormal glucose tolerance and insulin resistance still exist in the middle-aged mice with the history of GDM.There was no significant difference in serum ?2-microglobulin between the GDM group and the control group,and also between the GDM group and the metformin treatment group.The urinary microglobulin of the GDM group was still significantly higher than that of the control group.There was no significant difference in glomerular volume(HE staining)and in basement membrane thickness(PAS staining)between the GDM group and the control group.The serum IL-6 and TNF-? were significantly higher than those in the control group.The protein expressions of p-ERK,p-P38 and p-JNK were also significantly higher than those in the control group.Metformin significantly decrease the weight,glucose tolerance and insulin resistance of the middle-aged mice with the history of GDM.The urinary microprotein in the metformin treatment group decreased significantly.In the metformin treatment group,inflammatory cytokines of IL-6 and TNF-? in serum were significantly decreased.The protein expressions of p-ERK,p-P38 and p-JNK in the metformin treatment group decreased significantly.Conclusion :(1)The GDM model of C57 mice induced by HFD showed weight gain,abnormal glucose tolerance and insulin resistance,which suggested the GDM model of C57 mice was successfully induced.(2)Metformin can reduce the body weight,improve abnormal glucose tolerance and insulin resistance,and reverse renal dysfunction and pathological changes in GDM group.The protective effect of metformin on the kidney of GDM mice may be related to inflammatory factors and MAPK pathway.(3)Weight gain,abnormal glucose tolerance and insulin resistance still exist in the middle-aged mice with the history of GDM.serum ?2-microglobulin,an indicator of renal dysfunction,and pathological changes returned to normal after delivery in mice with the history of GDM.Urinary microprotein in the GDM group was still significantly higher than that in the control group,suggesting that GDM may be persistent in renal dysfunction after delivery.Metformin treatment during pregnancy can reduce the body weight,improve abnormal glucose tolerance and insulin resistance,and reverse renal dysfunction in the middle-aged mice with the history of GDM.The protective effect of metformin on the kidney in the middle-aged mice with the history of GDM may be related to inflammatory factors and MAPK pathway. |
PDF Full Text Request