Research On The Mechanism About Narcissoside Relieves Insulin Resistance

Diabetes Mellitus is a group of lifelong metabolic diseases characterized by chronic hyperglycemia caused by multiple causes.Diabetes is the third non-infectious leading cause of death besides cancer and cardiovascular disease.The incidence rate of type II diabetes in China has increased rapidly in recent years,and insulin resistance is one of the two main pathogenesis of type II diabetes.Narcissoside is a traditional Chinese medicine extract isolated from the microctis folium and liquorice.It has been reported that pharmacological activities against a variety of diseases.In this study,the effects and mechanism of narcissoside on insulin resistance were investigated by in vitro and in vivo.First,the in vitro cell models of insulin resistance(IR),endoplasmic reticulum stress(ERS)and mitochondrial dysfunction(MD)were established using HepG2 cells.MTT assay was performed to evaluate the effect of narcissoside on cell survival.Then the alleviation effects of different concentrations of narcissoside on the three models was investigated by glucose oxidase method.Western Blot was used to study the effects of narcissoside on the key proteins expression of IRS1-PI3K/AKT signaling pathway.The results showed that narcissoside did not affect HepG2 cell survival,and narcissoside significantly increased the glucose metabolism level of the three cell models.Narcissoside decreased the expression of GRP 78 and GSK-3β,while increased the expression of IRS1,PPARγ,p-AKT/AKT,p-GSK-3β in a does dependent manner.Narcissoside could alleviate IR-HepG2 cell insulin resistance by regulating IRS1-PI3K/AKT signaling pathway.To evaluate the treatment effect of narcissoside on type Ⅱ diabetes,we established the HFD-STZ mice model,and Narcissoside(20 mg/kg,50 mg/kg)was injected intraperitoneally for 40 days.The results showed that the fasting blood glucose level in HFD-STZ mice was significantly increased compared to that in control group mice,which was reduced significantly in narcissoside-H and narcissoside-L group.And after narcissoside treatment,the TG,TC,and LDL-C levels were significantly decreased,while HDL-C was increased compared with the HFD-STZ mice.Taken together,these findings indicate that narcissoside treatment could reduce glycaemia and promote lipid metabolism in T2 DM mice.Narcissoside could also protect the liver,kidney and pancreas of HFD-STZ diabetic mice.Finally,we conducted the network pharmacology experiments to further screen the key targets of narcissoside in alleviating type II diabetes mellitus.We found that the anti-diabetes target of narcissoside was PTGS2 and TNF.Narcissoside played an antidiabetic role mainly by regulating the metabolism pathway.Then we established the LPS-induced primary mouse peritoneal macrophage inflammation model to verify the above network results.In order to study the possible mechanism of narcissoside in the treatment of type II diabetes by alleviating inflammatory reaction,we used ELISA to detect the effect of narcissoside on the release of related inflammatory factors.The results showed that narcissoside could effectively reduce the release of TNF-α,IL-1βand IL-6 of LPS-induced primary mouse peritoneal macrophage which was consistent with the online results.In conclusion,narcissoside could promote glucose metabolism of IR,ERS and MD HepG2 cell models.And narcissoside could alleviate insulin resistance via IRSPI3K/AKT pathway.The in vivo experiments showed that narcissoside could improve glucose metabolism,regulate lipid metabolism and protect the organs of the HFD-STZ mice.Narcissoside may play an anti-diabetes role by alleviating inflammation through metabolic pathway.By the way,the network pharmacology results showed that narcissoside could treat diabetes by regulating PTGS2 and TNF key target proteins effect the metabolic pathways;and narcissoside could alleviate inflammation by reducing the release of inflammatory cytokines of LPS-induced primary mouse peritoneal macrophage.Therefore,narcissoside could treat diabetes and it is worth to be researched.This study has provided theoretical basis for developing a new type of PPARγ agonist drugs,and provides a new target and direction for the treatment of type II diabetes.