摘要Objective:To investigate the relationship between Jiaotai pill(JTP),its main component berberine(BBR),and the serotonin(5-HT)system in regulating islet hormone secretion and alleviating pancreatic β-cell dysfunction during type 2 diabetes mellitus(T2DM)progression.Methods:T2DM rat model was established using a high-fat diet and streptozotocin injection.JTP,BBR,and Metformin were intragastrically administered for 35 days.The analyzed indices included blood glucose,blood lipids,islet hormones,and proteins related to 5-HT synthesis,secretion,and transport.Additionally,an in vitro model of glucose injury in islet cells was established to study the effects of JTP and BBR on islet hormone secretion following tryptophan hydroxylase 1(TPH1)inhibition.Results:JTP and BBR significantly improved blood glucose and lipid levels and islet morphology in T2DM rats.Both models exhibited reduced islet 5-HT levels and impaired islet hormone secretion.However,the administration of JTP and BBR reversed these effects.Furthermore,JTP and BBR upregulated the expression of TPH1(P=.0194,P=.0413)transglutaminase 2(TGase2;P=.0492,P=.0349),serotonin transporter(SERT,P=.0090),and 5-hydroxytryptamine 1F receptor(5-HT1FR)in the islet 5-HT pathway(P=.0194).In the cell model,the regulatory effects of JTP and BBR on islet hormone levels were significantly weakened after TPH1 inhibition(P=.001),suggesting that JTP and BBR influence islet hormone secretion through the pancreatic 5-HT system.Conclusion:The islet 5-HT system is correlated with islet hormone secretion dysfunction in T2DM.JTP and BBR can improve islet hormone secretion by activating the TPH1/TGase2/SERT/5-HT1FR pathway in the islet 5-HT system in T2DM rats.