Regulation Of Fat-specifc Protein 27 In Fat Hydrolytic Metabolism Induced By Bariatric Surgery

Objective: To study the effects of sleeve gastrectomy(SG)and Roux-en-Y Gastric Bypass(RYGB)on food ration,massing,fatty degeneration of liver and fat distribution of obese rats and the changes in FSP27 expression.To study the regulation effects on lipid synthesis and decomposition and the effects on energy homeostasis of FSP27 in adipose tissue of obese rats and lean rats induced by bariatric surgery,as well as in mature 3T3-l1 adipose cells.At the same time,to explore the effects on PPAR?/FSP27 and its downstream lipase caused by energy and nutrient environmental factors.In order to solve the problem that the weight of patients cannot be reduced to the expected level or the patients even regain weight after bariatric surgery,and to provide theoretical and experimental basis for finding the potential way to achieve weight loss by assisting or even replacing invasive surgery.Methods:The first part of this study established the rat models of obesity,obesity control,Sleeve gastrectomy for obesity,Roux-En-Y of obesity.After 4 weeks,the food intake and body weight of rats in each group were continuously measured 4weeks after surgery.The content of triglyceride in plasma,adipose tissue and liver was detected on the 28 th day after surgery.The morphological changes of hepatocytes were observed by HE staining and oil red staining.The improvement of hepatic steatosis in obese rats before and after bariatric surgery was compared.The body composition and fat distribution of rats were measured by dual energy X-ray measurement.The body composition and fat distribution of rats were measured by dual energy X-ray.FSP27 contents,cells and lipid droplet morphology in white and brown adipose tissue of rats were observed by immunohistochemical staining.q RT-PCR was used to detect FSP27 and protein UCP1 labeled by Brown fat.In the second part of the study,Western blot was used to detect the protein expression of FSP27,HSL,p-HSL,ATGL,CGI-58,DGAT1 and DGAT2 in the trunk fat of rats at 2and 4 weeks after operation.3T3-L1 preadipocyte after the induction and maturation were respectively cultured in the control medium(DMEM medium with 10% FBS and 5mmol /L glucose),the high-fat medium(0.2 mmol/L,0.5 mmol/L,1 mmol/L palmitic acid),the high-glucose medium(10 mmol/L,25 mmol/L,35 mmol/L glucose),the high-nutrient medium(20%,30%,50% FBS),(0.2mmol /L,0.5mmol /L and 1mmol /L palmitic acid)for 48 hours,and the changes in FSP27 expression were detected by Western blot and the optimal concentration was screened.The expression of FSP27 and subcellular localization in adipocytes were detected by immunofluorescence and the expression of HSL and ATGL was detected by Western blot.The induced mature 3T3-L1 adipocytes after silenced FSP27 were cultured in control medium and optimum concentration medium of high-fat,high-sugar and high-nutrient and the protein expression of HSL and ATML was detected again.In the third part of this study,the content changes of PPAR? of epididymal fat in rats were detected at 2 and 4 weeks after surgery.The effects of high fat,high glucose and high nutrition on PPAR-? in mature 3T3-L1 adipocytes were detected by q RT-PCR and Western blot.PPAR-? was overexpressed or silenced in 3T3-L1 preadipocytes by si RNA and plasmid transfection.The content and protein expression of FSP27,HSL and ATGL were detected.After overexpression of PPAR-? and silencing FSP27 in3T3-L1 cells were induced and matured,they were cultured in high-fat,high-glucose and high-nutrient medium.The expression of PPAR-?,FSP27,HSL and ATGL in3T3-L1 cells was detected.Results: In the first part of this study,bariatric surgery(SG and RYGB)effectively reduced the postoperative food intake of rats.The postoperative weight of rats in bariatric surgery group decreased rapidly until the beginning of the 4th week.SG and RYGB could effectively reduce the TAG content in plasma,fat and liver,and significantly improved the hepatic steatosis in obese rats.SG and RYGB significantly reduced the body fat volume 4 weeks after operation,but hardly changed the lean body weight.Trunk fat loss was the most significant in the reduction of body fat caused by bariatric surgery.SG and RYGB reduced the diameter of adipocytes in the epididymis and perirenal tissue of rats,made multilocular lipid droplets appeared,increased the expression of FSP27 and UCP1 and promoted the transformation of white fat to brown fat.In the second part of this study,the concentration of FSP27 protein in white adipose tissue after bariatric showed a dynamic change from low to high.In response to the change,the content of lipase increased rapidly to gradual decrease after operation,but was always higher than that of obese control and sham-operated rats.However,the triglyceride synthase decreased only slightly and recovered to the level close to that of obese(control)rats.The increase of FSP27 in brown interscapular fat was earlier than that in white fat.High-fat,high-sugar and high-nutrient medium all significantly reduced the content of FSP27 protein.The optimum concentration of palmitic acid was 0.5 mmol/L,glucose was 35 mmol/L and serum was 50%.The decrease of FSP27 protein concentration in the high-fat environment did not cause significant changes in HSL and ATGL.The hyperglycemia environment caused the decrease of FSP27 and the increase of HSL,but there was no change in ATGL.The decrease of FSP27 was coexisted with the increase of ATGL,while the decrease of HSL was slight.However,after FSP27 gene was silenced,high fat,glucose and nutrition did not change HSL and ATML protein concentration in adipocytes.In the third part of this study,the content changes of PPAR? of epididymal fat in rats showed a dynamic change from low to high.The content of PPAR? in mature adipocytes was significantly lower than that in the control group due to the effects of high fat,high glucose and high nutrition.The induced mature 3T3-L1 adipocytes after silenced PPAR?,the m RNA and protein contents of FSP27 and ATGL were significantly decreased,and the HSL protein level was decreased.Overexpression of PPAR? increased the the protein and m RNA expression of FSP27,ATGL and HSL.The high-fat,high-glucose,high-nutrient medium did not over-express PPAR? and the m RNA and protein expression of HSL and ATGL were not significantly changed in mature 3T3-L1 adipocytes of FSP27 silenced cells.Conclusions: FSP27 has the function of feedback balancing lipid decomposition and storage,and its expression changes with the change of energy and nutrient supply.Under the influence of energy and nutrient environment,FSP27 positively regulated by PPAR-?and regulates the expression of HSL and ATGL,mediates the formation of lipid droplets and inhibits the excessive hydrolysis and accumulation of fat.