The Influence Of Whiting Epicardial Brown Adipose Tissue On Coronary Atherosclerosis Induced By Activation Of JAK-STAT3 Pathway

Part Ⅰ The influence of whiting epicardial brown adipose tissue on coronary atherosclerosisObjective:In this study, we probed whether the whiting of epicardial brown adipose tissue exists in the process of coronary atherosclerosis.Methods:Thirty rabbits were fed with a high-fat diet for 0,8,12 weeks. Biochemical tests, histopathology and immunohistochemistry, transmission electron microscopy (TEM), and quantitative real-time PCR studies were performed.Results:8-week and 12-week group showed significantly higher levels of serum TG, TC, LDL-C, hs-CRP, IL-6, TNF-α, Leptin, MMP-9, PAPP-A and sE-selectin as compared with 0-week group, and significantly lower levels of serum HDL-C and Adiponectin (p<0.05).8-week and 12-week groups showed a larger area of coronary atherosclerosis plaques than 0-week group (p<0.05). The H&E staining of EAT showed a significantly fewer number of adipocytes per field in 8-week and 12-week group as compared with 0-week group, whose average size of adipocytes was significantly larger (p<0.05). Immunohistochemical staining of EAT showed that the levels of UCP-1 and CD31 were significantly lower in 8-week and 12-week group as compared with 0-week group, while the levels of Leptin and macrophage were significantly higher (P<0.05). In 8-week and 12-week group, the mitochondrial number were significantly decreased in EAT as compared with 0-week group (p<0.05). In 0-week group, the mRNA expression of UCP-1 and PPAR-γ in EAT was significantly higher than in eWAT, while the expression of Leptin was significantly lower (p<0.05). But there was no significantly difference between EAT and sBAT (p>0.05). It was indicated that EAT was a kind of BAT in healthy condition. Compared with 0-week group, the mRNA expression of UCP-1 and PPAR-y in 8-week and 12-week group was significantly lower, while the expression of Leptin was significantly higher (p<0.05).Conclusions:The whiting of epicardial brown adipose tissue exists in the process of coronary atherosclerosis.Part Ⅱ IL-6 induces epicardial adipose tissue brown-to-white by activation of the JAK-STAT3 pathwayObjective:In this study, we probed how epicardial brown adipose tissue (BAT) transformed into white adipose tissue (WAT).Methods:Ten rabbits were fed normal diet. Cells culture and quantitative real-time PCR studies were performed.Results:With the increasing of IL-6 concentration, the mRNA expression of UCP-1 and PPAR-y gradually reduced, while the expression of Leptin and STAT3 increased (p< 0.05). Under the same concentration of IL-6, with the increasing of JSI-124 concentration, the mRNA expression of UCP-1 and PPAR-y gradually increased, while the expression of Leptin and STAT3 reduced (p< 0.05).Conclusions:IL-6 could induce the transformation from epicardial BAT into WAT by activation of JAK-STAT3 pathway.