Study The Protective Mechanism Of Potentilla Discolor Aqueous Extract On Rats Pancreatic Islet β Cells

Background Diabetes is a metabolic disorder diseases that the body control the dysfunction of glucose and secretion imbalance of insulin.According to the survey in2013,the china adult morbidity rate of diabetes has risen to 11.6 %,the number of them estimates up to 113 million,about 1/3 of the global number.According to the WHO,Diabetes has become the third major disease that threat human health and life safety after the tumor and cardiovascular disease.Islet beta cells are the only cells that secrete insulin.Its normal number and function is the necessary condition to maintain the body balance.Forkhead box O(FoxO)is a kind of important transcription factors that can regulate cell differentiation,proliferation and survival for fat cells,liver cells,islet beta cells and the others.FoxO1 regulate and control beta cell number and function and it plays an important role in diabetes development.Potentilla Discolor Bunge is a rosaceae plant.It can qingrejiedu,stop dysentery and bleeding and eliminate the sensation of hot and dry,to alleviate the symptoms of diabetes.People usually drink PDB water to treatment diabetes.Studies have shown that PDB can significantly reduce the blood sugar,repair the beta cells,increase insulin release in the Streptozotocin-Induced injury model.This shows PDB have a protective effect for islet cells.Now,much number of studies have shown that PDB can antioxidant,improve lipid metabolism and insulin resistance to decrease blood sugar.And there are other mechanism is unclear.Aim To investigate the protective mechanism of Potentilla discolor aqueous extract on RIN-m5 f cells in the Streptozotocin-Induced injury model.Methods Potentilla discolor aqueous extract was extracted by rotary evaporators and thermoelectric thermostat drying box.The injury model was induced by Streptozotocin(STZ,4 mmol/L,1 h).Cells were treated with different concentrations of PDB extracts(0.25 mg/ml,0.5 mg/ml,1 mg/ml)for different time(24 h,48 h,72 h).Cell viability were evaluated with MTT assay kit(Sigma,USA)and insulin secretion were evaluated with ELISA kit according to the manufacturer’s instructions.The related genes level were measured with Western Blot.Results ⑴It was extracted 517.5 g by water from 3600 g PDB.⑵Pretreated the RIN-m5 f cells for 1 h,different concentration(0.25 mg/ml,0.5 mg/ml,1 mg/ml)and different time(24 h,48 h,72 h)of Extract of P.discolor on RIN-m5 f cells,viable cells were evaluated with MTT assay kit(Sigma,USA)according to the manufacturer’s instructions.(1)Cell growth curve: the number of cells in STZ injury group wassignificantly lower than that in the control group(P<0.01).Compared with the injury group,1 mg/ml PDB extracts could increase the number of cells in a time-dependent manner.(2)Cell viability: the number of cells in STZ injury group was significantly lower than that in the control group(P<0.01).Compared with the injury group,0.25mg/m,0.5 mg/m,1 mg/ml PDB extracts could increase the number of cells in a dose-dependent manner.⑶Cells were treated with different concentrations of PDB extracts for different time.The culture medium was collected and insulin content was determined by using ELISA kit according to the manufacturer’s instructions:(1)after 24 h,48 h,72 h treatment with PDB extracts,The total insulin secretion in the injured group Significantly decreased compared to control group(P<0.01).Compared to injury group,The total insulin secretion increased in cells treated by PDB extracts in a dose-dependent manner.(2)after 24 h,48 h,72 h treatment with PDB extracts,insulin secretion of every cell in the injured group significantly decreased compared to control group(P<0.01).Compared to injury group,insulin secretion of every cell increased in cells treated by PDB extracts in a dose-dependent manner.⑷Compared to control group,FoxO1 and p-Fox O1 protein level in injured group decreased(P<0.05).Compared to injury group,Fox O1 protein level did not change significantly but p-Fox O1 protein level increased significantly in cells treated by PDB extracts in a dose-dependent manner Conclusions It is demonstrated that EPD inhibition the cell damage,improved the cell viability,promoted insulin secretion,increased the protein level of p-FoxO1.EPD played a protective role for the Streptozotocin-Induced injury model.The mechanism may be related to increase p-Fox O1,which further increase the number and improve the function of β cells.