Roux-en-Y Gastric Bypass On Natriuretic Peptide Receptors Of Adipose Tissue In Obese Diabetic Rats

Objective:A decrease in tissue lipotoxicity is one of the crucial mechanisms by which Roux-en-Y gastric bypass(RYGB)improves insulin resistance.Mechanisms leading to a post-RYGB reduction in lipid accumulation are poorly understood.The natriuretic peptide(NP)system plays an important part in regulating lipid metabolism.We explored the effects of RYGB on adipose tissue natriuretic peptide receptors and the possible mechanisms.Methods:Male Sprague-Dawley rats with obesity and diabetes were divided into three groups:diabetic RYGB,diabetic sham and diabetes(n = 8 per group).Four weeks after surgery,the parameters of body weight,food intake rate,body composition,insulin sensitivity,lipid content,plasma glucagon-like peptide-1(GLP-1)and NPs were assessed to evaluate metabolic changes.The messenger RNA and protein expression levels of NP receptors and key regulatory enzymes of lipolysis in adipose tissue were quantified.Results:RYGB markedly reduced body weight,lipid levels,and improved insulin resistance.The natriuretic peptide receptor A(NPRA)to C(NPRC)ratio and lipolysis markers in adipose tissue were significantly higher in the diabetic RYGB group than in diabetic sham and diabetic group at both mRNA and protein levels(P<0.05)4 weeks post-RYGB.The adipose tissue NPRA to NPRC ratio correlated positively with the plasma GLP-1 level(P<0.05).Conclusions:This study identifies a critical function for NP receptors in lipid metabolism after RYGB.RYGB upregulates the NPRA to NPRC ratio and accelerates lipolysis,which may play a key role in reducing fat over load in adipose tissue.We suggest that the upregulation of the NPRA to NPRC ratio after RYGB may be related to the restoration of surgery-induced GLP-1 levels.