Effect of Interleukin-6 on Lipolysis in Porcine Adipocytes

The purpose of the study was to explore the effect of interleukin(IL)-6 on lipolysis in porcine adipocytes and the underlying molecular regulation mechanism.Porcine primary adipocytes were cultured and incubated with different concentrations of IL-6(0,25,50,75 and 100 ng·mL-1) for 24 or 48 h.Then,the glycerol released into the media was measured as an indicator of the lipolysis.Lipid accumulation morphology was visualized by phase-contrast microscopy.Further,gene expressions of perilipin A,peroxisome proliferator-activated receptor-gamma2(PPAR γ2),hormone-sensitive lipase(HSL) and adipose triglyceride lipase(ATGL) were analyzed with semi-quantitative RT-PCR,and their protein level were determined with Western blot.The results showed that IL-6 stimulated lipolysis in differentiated porcine adipocytes in a dose-and time-dependent manner.Meanwhile,the mRNA and protein level of PPAR γ2 and perilipin A were significantly reduced.Although the expression abundance of HSL mRNA was significantly elevated,its protein level had no marked changes.The mRNA and protein level of ATGL were not affected.These findings imply that chronic high dose of IL-6 directly stimulates lipolysis in porcine adipocytes through repressing PPAR γ2 and its target gene perilipin A.