Abstract
Objective To investigate the effect of exercise training on the expression of peroxisome proliferator-activated receptor (PPAR)-δ in muscle and adipose tissue in high fat diet induced obese rats and to explore the possible mechanism of improving insulin resistance. Methods Sixty male nine-week old Wistar rats with a weight of 135 to 150 g were randomly selected by using random number table for production of obese rats models with high fat diet for 6 weeks, another 20 rats were fed with ordinary feed as control. A total of 54 rat models were established successfully and were divided randomly into three groups: high-fat diet group (HFD), high fat diet whilst exercise group (E-HFD), exercise after high fat diet group (HFD-E), 18 rats in each group; and 16 rats with ordinary diet were set as control: the normal diet group (RD). The rats in all groups were given exercise training for 6 weeks according to the methods from literature. After the exercise training was done, the body weight, levels of tumor necrosis factor(TNF)-α, leptin, interleukin(IL)-1, fasting glucose, fasting insulin, insulin sensitivity index (ISI) and expression of PPAR-δ, GLUT-4, PI3K mRNA and PPAR-δ protein in muscle and adipose tissue in the groups were investigated and compared. Two-side t test was used in the comparison of data between the groups. Results The ISI in group HFD, E-HFD and HFD-E was 1.13±0.21, 2.09±0.32 and 1.80±0.34, respectively; and it increased for 71.1% and 45.7% in group E-HFD and HFD-E compared to that in group HFD (all P<0.05). Compared with that in group HFD, the TNF-α level in group E-HFD and HFD-E decreased for 20.0% and 9.2% respectively ((101±24)ng/L, (81±16) ng/L and (92±19) ng/L, respectively)(all P<0.05). Compared to those in group HFD, the level of leptin and IL-1 in group E-HFD and HFD-E decreased significantly(all P<0.05). The expression level of PPAR-δ, GLUT-4, PI3K mRNA in muscle and fat tissue in group E-HFD and HFD-E increased significantly compared with those in group HFD, especially in group E-HFD(all P<0.05). Compared with that in group HFD, the expression of PPAR-δ in muscle and fat tissues in group E-HFD increased for 388.4% and 203.2%, respectively(all P<0.05); and the expression of PPAR-δ in muscle and fat tissues in group E-HFD increased for 272.9% and 117.9%, respectively(all P<0.05). Conclusion Exercise training improves insulin resistance and decreases the level of serum leptin, TNF-α and IL-1 in high fat diet induced obese rat, and this effect is probably mediated by up-regulation of PPAR-δ. Key words: Obesity; Exercise; Rats; Insulin resistance; Peroxisome proliferator-activated receptor-δ
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call