The Effects Of Metformin On Maternal And Transgenerational Metabolism In Gestational Diabetes: A Mouse Model

Objective: Gestational diabetes mellitus(GDM)is defined as glucose intolerance that develops or is first recognised during pregnancy.It affects an estimated 17.5% of pregnancies in China.Treatment options for GDM are limited.Metformin has shown significant promise as a treatment for type 2 diabetes mellitus,but effects on the GDM and the long-term implications of use during pregnancy remain poorly understood.These study were carried out to investigate the effects of metformin on maternal and transgenerational metabolism in gestational diabetes with a mouse model.Methods:(1)To validate the GDM phenotype on Leprdb/+ mouse model and dietary(HFD)induced mouse model.During pregnancy,the body weight of mice were measured,as well as oral glucose tolerance test(OGTT).After killing mice,blood sample were collected to analyze the fasting blood glucose,insulin and leptin concentrations.Maternal organs and fetuses were weighted and measured.(2)After the GDM mouse model was established,metformin were given through gavage to GDM mice.During pregnancy,the body weight and OGTT were measured.After killing mice,blood sample were collected to analyze the fasting blood glucose,insulin,leptin,triglyceride(TG),total cholesterol(TC),free fat acid(fFA),low density lipoprotein(LDL),and high-density lipoprotein(HDL)concentrations.Maternal organs and fetuses were weighted and measured.H&E staining and oil red O staining for hepatic tissue were used to check the liver steatosis.AMP-activated protein kinase(AMPK),Acetyl-coenzyme A carboxylase(ACC),Phosphatidylinositol 3 '-kinase(PI3K),Protein kinase B(Akt),c-Jun N-terminal kinase(JNK),Extracellular regulated protein kinases(ERK),P38 in hepatic and muscular tissue were determined by Western blotting.AMPK? 1?ACC?Akt1?Tumor necrosis factor ?(TNF?),Interlukin-1?(IL-?)and Interlukin-6(IL-6)mRNA in hepatic and muscular tissue were determined by RT-PCR.(3)Established F1 generation and F2 generation.F1 mice were fed to 26 weeks old and given the HFD as a second hit respectively at 3 weeks old and 20 weeks old.F2 mice were fed to 28 weeks old and were given the HFD as a second hit.Body weight of F1 and F2 mice were measured weekly,and the main organ phenotypes of F1 and F2 mice were measured after sacrifices.Before and after second hit,F1 mice were measured OGTT and insulin tolerance test(ITT),and F2 mice were measured OGTT,ITT,and blood pressure.Results:(1)The Leprdb/+ transgenic mouse lost diabetic phenotypes during the first and second pregnancy because impaired glucose tolerance and insulin resistance were not observed anymore.The HFD induced C57BL/6J mouse were shown impaired glucose tolerance,insulin resistance,higher weight gain over pregnancy and fetal:placental ratio.So HFD induced mouse model was succussed.(2)In maternal study,metformin can obviously improve glucose tolerance,insulin resistance and liver steatosis in GDM mice,and decrease maternal body weight,TG,fFA,and LDL concentrations.Metformin increased phosph-AMPK,phosph-ACC,phosph-PI3 K,phosph-Akt,phosph-JNK,phosph-ERK and phosph-P38 expression level in hepatic and muscular tissue.At the same time,metformin can significantly reduce the TNF?,IL-1? and IL-6 mRNA expression level in hepatic and muscular tissue.(3)In F1 generation,metformin can decrease male offspring body weight and improve the glucose tolerance and insulin sensitivity after giving the second hit.Different intrauterine background of F1 male offspring mated with same maternal gene background F1 female offspring to produce F2 generation,after adding HFD as a second hit to F2 offspring,whose body weight and blood pressure in male were decreased by metformin as a transgenerational effect,as well as glucose tolerance improved.Conclusion:(1)Leprdb/+ transgenic mouse in no longer a spontaneous GDM model;HFD induced C57BL/6J mice could be typically used as a GDM model.(2)Metformin can improve maternal glucose and lipid metabolism,and decrease inflammation markers in GDM mouse through AMPK-ACC,PI3K-Akt,MAPK(JNK/ERK/P38)signalling pathways.(3)Metformin can improve F1 and F2 generation metabolism and decrease body weight in GDM mouse as a transgenerational effect.