中药复方汉唐平调控Galectin-3表达及PI3K/Akt/FoxO1信号通路改善db/db2型糖尿病小鼠胰岛β细胞功能的作用机制OA

Objective To investigate the mechanism by which the Chinese herbal formula Hantangping improves islet β-cell function in db/db type 2 diabetes mellitus(T2DM)mice,based on Galectin-3 expression and the phosphatidylinositol 3-kinase(PI3K)/protein kinase B(Akt)/forkhead box protein O1(FoxO1)signaling pathway.Methods Forty db/db mice were randomly divided into a model group,a metformin group(30 mg·kg-1),a Hantangping group(50.6 g·kg-1),and a GB1107 group(Galectin-3 inhibitor,30 mg·kg-1),with 10 mice per group.An additional 10 C57BL/6J mice were selected as the control group.All groups received gavage administration once daily at a volume of 10 mL·kg-1 for 12 consecutive weeks.At the end of the 12-week intervention,fasting blood glucose(FBG)levels were measured.An oral glucose tolerance test(OGTT)was performed,and the area under the curve for OGTT(AUCOGTT)was calculated.Serum fasting insulin(FINS)levels were detected by ELISA.Histopathological changes in pancreatic tissue were observed using hematoxylin and eosin(HE)staining.Insulin(INS)expression in pancreatic tissue was detected by immunofluorescence.Expression of the macrophage marker cluster of differentiation 68(CD68)and Galectin-3 in pancreatic tissue was detected by immunohistochemistry.mRNA expression levels of musculoaponeurotic fibrosarcoma oncogene homolog A(MafA),pancreatic and duodenal homeobox 1(Pdx-1),Nanog homeobox protein(Nanog),and neurogenin 3(Ngn3)in pancreatic tissue were detected by RT-qPCR.Protein expression levels of MafA,Pdx-1,Nanog,Ngn3,and key proteins of the PI3K/Akt/FoxO1 signaling pathway in mouse pancreatic tissue were detected by Western Blot.Results Compared with the control group,FBG and AUCOGTT levels were significantly increased(P＜0.001),while FINS levels were significantly decreased(P＜0.001)in the model group.Pancreatic tissue structure was severely damaged,with widespread degranulation of acinar cells,marked atrophy and a reduced total number of islets,blurred boundaries,irregular shapes,significantly decreased islet cell counts,loose cell arrangement,numerous cytoplasmic vacuoles,and extensive mononuclear cell infiltration within and around the islets.Islets were markedly atrophied,with reduced and disorganized cell numbers,and insulin secretion levels were significantly reduced(P＜0.001).Expression levels of the islet macrophage marker CD68 and the inflammatory factor Galectin-3 were significantly increased(P＜0.001).mRNA and protein expression levels of islet β-cell functional markers MafA and Pdx-1 were significantly decreased(P＜0.001),while mRNA and protein expression levels of dedifferentiation markers Nanog and Ngn3 were significantly increased(P＜0.001).PI3K protein expression levels and phosphorylation levels of Akt and FoxO1 proteins in pancreatic tissue were significantly decreased(P＜0.001).Compared with the model group,FBG levels were significantly decreased in all treatment groups(P＜0.001).Pancreatic tissue damage was markedly alleviated,with increased islet number,more regular boundaries,relatively intact structure,and a degree of recovery in islet cells,including increased cell counts,reduced cytoplasmic vacuolation,and reduced mononuclear cell infiltration within and around the islets.Islet cell numbers increased,and insulin secretion levels were significantly elevated(P＜0.01,P＜0.001).Expression levels of CD68 and Galectin-3 in islets were significantly reduced(P＜0.05,P＜0.01,P＜0.001).mRNA and protein expression levels of MafA and Pdx-1 in pancreatic tissue were significantly increased(P＜0.05,P＜0.01,P＜0.001),while mRNA and protein expression levels of Nanog and Ngn3 were significantly decreased(P＜0.05,P＜0.01,P＜0.001).PI3K protein expression levels and FoxO1 protein phosphorylation levels were significantly increased(P＜0.05,P＜0.01,P＜0.001).Compared with the model group,FINS levels were significantly increased(P＜0.05,P＜0.01)and AUCOGTT levels were significantly decreased(P＜0.05)in the Hantangping and GB1107 groups.Akt protein phosphorylation levels in pancreatic tissue were significantly increased in these two groups(P＜0.05,P＜0.01).Conclusion Hantangping can ameliorate glucose metabolism disorders in db/db T2DM mice,inhibit the expression of dedifferentiation markers Nanog and Ngn3,and upregulate the expression of functional markers MafA and Pdx-1,thereby effectively reversing islet β-cell dedifferentiation,restoring their normal phenotype and function,and improving insulin secretion.Its mechanism may be related to inhibiting the overexpression of Galectin-3 and enhancing the activity of the PI3K/Akt/FoxO1 signaling pathway.