Regulatory Effect Of GSK3β On Glycolipid Metabolism In Hepatopancreas Of Schizothorax Prenanti

Schizothorax prenanti is an important economic fish in the upper reaches of the Yangtze River,mainly distributed in the Minjiang River,Dadu River and the upper reaches of the Yangtze River.The decline of wild resources and the increase of people’s consumption ability,the factory production of Schizotharax prenanti came into being.However,due to improper feeding of compound feed and irregular management,it is easy to induce the disturbance of glucose and lipid metabolism in fish.The liver is the main component of the internal organs of the fish,and is an important metabolic organ.It plays an important role in maintaining the balance of glucose and lipid metabolism in the fish.Glycogen synthesis kinase（GSK3）is a serine/threonine kinase that plays an important role in glycogen synthesis,metabolism and growth and development.The GSK3β gene was isolated and cloned by the research team in the previous period,but it is unclear whether the GSK3β can regulate the glucose and lipid metabolism in Schizothorax prenanti.In this research,the study was carried out using Schizothorax prenanti.Firstly,the tissue distribution of GSK3β protein in Schizothorax prenanti was studied by Western Blotting.Then,50 mg/m L LiCl and 0.7% Na Cl were injected intraperitoneally for continuous treatment.On 8d,the serine phosphorylation of GSK3βand GSK3β under LiCl treatment in Schizothorax prenanti was detected,and plasma biochemical indicators,hepatopancreas TG content,fatty deposition-related genes,Tyr705 phosphorylation of STAT3 and STAT3,and blood glucose,tissue glycogen content,glycolysis,gluconeogenesis and glycogen metabolism-related gene expression The main results are as follows.1.Tissue expression analysis performed by Western Blotting found that GSK3β protein was specifically highly expressed in the hepatopancreas and low in ovarian tissue,with the lowest expression in white muscle and middle kidney tissue.2.Western Blotting results showed that LiCl treatment can significantly reduce the expression of GSK3β protein,and at the same time significantly promote the increase of Ser9 phosphorylation of GSK3β.3.The effects of LiCl on lipid metabolism in Schizothorax prenanti were detected by enzyme-labeled method,qPCR and Western Blotting.The results showed that LiCl can significantly reduce the content of TG,TC and HDL-C in plasma,while significantly reducing the content of TG in hepatopancreas;significantly down-regulate hepatopancreas C/EBPα,FABP4,ACC and FAS gene expression;significantly reduce Tyr705 phosphorylation of STAT3.4.Hexokinase method,anthrone method,and qPCR were used to analyze the effect of carbohydrate metabolism under LiCl treatment in Schizothorax prenanti.It was found that LiCl does not affect the glucose level in plasma,but it significantly reduces hepatopancreas glycogen and white muscle glycogen content without affecting red muscle and brain glycogen content.At the same time,it significantly reduces the gene expression of PK and G6 Pase.It has no effect on the gene transcription of GYS1 and PYGL.To sum up,the specific expression of GSK3β protein in the hepatopancreas of Schizothorax prenanti showed that GSK3β protein played an important role in the hepatopancreas tissue of Schizothorax prenanti.LiCl significantly down-regulates the expression of GSK3β protein in the hepatopancreas of Schizothorax prenanti,and at the same time significantly promotes the increase of GSK3β（Ser9）phosphorylation,thereby reducing the activity of GSK3β protein.LiCl treatment can significantly reduce the content of TG,TC and HDL-C in plasma and reduce the content of TG in hepatopancreas.And significantly reduced C/EBPα,FABP4,ACC and FAS gene expression in the hepatopancreas.It was further found that inhibition of the GSK3βprotein significantly reduced the phosphorylation level of the Tyr705 site of the STAT3 protein,indicating that LiCl can regulate the fatty deposition process in the hepatopancreas through the STAT3 signaling pathway.Inhibition of GSK3β protein in vivo significantly reduces glycogen content in the hepatopancreas,and regulates the hepatopancreas glucose metabolism process of Schizothorax prenanti,by downregulating the expression of the glycolytic key enzyme PK gene and gluconeogenesis key enzymes（FBPase and G6Pase）.