Effect Of Visfatin On The Expressions Of Fibroblast Growth Factor 23 And Bone Morphogenetic Protein-9 In Liver Of KKAY Mice

Objective:To investigate the expressions of fibroblast growth factor 23（FGF23）and bone morphogenetic protein-9（BMP-9）in the liver of KKAy diabetic mice,and preliminarily explore and verify whether adipose factor visfatin can affect the expressions of FGF23 and BMP-9 in liver tissue of diabetic mice through the mechanism of phosphoinositide 3-kinase（PIK3）/protein kinase B（Akt）signal pathway.Methods:40 8-week-old C57BL/6J mice were randomly divided into normal control group and high-fat diet group.The normal control group was randomly divided into normal diet group（ND group,n=7）and normal diet+visfatin overexpression adenovirus vector intervention group（NV group,n=7）,high-fat diet group was randomly divided into high-fat group（HFD group,n=7）and high-fat+visfatin overexpression adenovirus vector intervention group（HFV group,n=7）.20 8-week-old KKAy mice were fed with special high-fat diet for 8 weeks,and fasting blood glucose was measured every week.Two consecutive times of fasting blood glucose≥13.9mmol/L were defined as diabetic model.The diabetic mice were randomly divided into diabetic group（DM group,n=7）and diabetes+visfatin overexpression adenoviral vector intervention group（DV group,n=7）.In NV,HFV and DV groups,visfatin overexpression adenovirus vector（100μl）;The remaining groups were given a single injection of the same dose of empty vector virus.The levels of glucose,lipid and insulin in six groups mice were measured.Glucose tolerance test（GTT）and insulin tolerance test（ITT）were performed to detect blood glucose and insulin at each time point,draw the corresponding curve,calculate the area under the curve(AUC_GTT,AUC_ITT)and homeostasis model（HOMA-IR）was calculated to evaluate insulin resistance,insulin sensitivity index（ISI）was calculated to evaluate insulin sensitivity.The pathological changes of liver tissue of mice were observed by HE staining under light microscope.At the same time,the protein expressions and phosphorylation levels of cytokines FGF23,BMP-9 and key molecules PI3K,Akt in PI3K/AKT signal pathway and their downstream Fox O1 were detected by Westernblot,the gene expression levels of FGF23 and BMP-9 were detected by RT-PCR.Results:（1）Glucose and lipid metabolism related indicators.Before visfatin injection,compared with ND and HFD groups,the body weight,FBG,Fins,HOMA-IR,TG,TC,LDL-C and FFA of The DM group were significantly increased,AUC_GTTand AUC_ITTwere increased,ISI was decreased（P<0.05）.After visfatin intervention:compared with DM group,the body weight,FBG,fins,HOMA-IR,TG,TC,FFA levels of DV group were decreased,AUC_GTTand AUC_ITTvalues were decreased,ISI was increased（P<0.05）.Key proteins and genes of PI3K/Akt signaling pathway.Before visfatin injection:compared with ND group,PI3K and p-Akt/Akt protein levels in DM group were significantly decreased;Compared with HFD group,the expression of PI3K protein was decreased in DM group;Compared with ND and HFD groups,the protein levels of Fox O1and p-Fox O1 were increased,and the gene expressions of PEPCK and G-6-P were increased in DM group（P<0.05）.After visfatin injection,the protein levels of PI3K and p-Akt/Akt in DV group were higher than those in DM group,the protein levels of Fox O1were lower,and the gene expressions of PEPCK and G-6-P were lower than those in DM group（P<0.05）（3）FGF23 and BMP-9.Before visfatin injection,the expression of FGF23 protein and gene in DM group was significantly higher than that in ND and HFD groups,while the expression of BMP-9 protein and gene was decreased（P<0.05）.After visfatin intervention,the protein and gene levels of FGF23 in DV group were significantly lower than those in DM group,while the protein and gene levels of BMP-9 in DV group were significantly higher than those in DM group（P<0.05）.Conclusion:Visfatin may improve glucose and lipid metabolism and insulin resistance in KKAy diabetic mice through PI3K/Akt signaling pathway,reduce liver FGF23 expression and increase BMP-9 expression.