Influence of exercise on expressions of PPAR-γ and Glut-4 in mice with insulin resistance / 心血管康复医学杂志

ABSTRACT

Objective: To observe influence of exercise on expressions of peroxisome proliferators-activated receptor-γ (PPAR-γ) and glucose transporter-4 (Glut-4) in skeletal muscle tissue of mice with insulin resistance (IR) induced by high fat diet, and preliminarily investigate mechanism of swimming training improves IR. Methods: A total of 30 eight-week-old healthy male C57BL /6J mice were randomly divided into normal diet group (n=10), high fat diet group (n=10) and high fat diet + exercise group (HE group, n=10, mice received 12-week swimming training). Body weight and fasting blood glucose (FBG) of mice were measured every week. After 12-week swimming training, fasting insulin (FINS) was measured by radioimmunoassay and IR index (IRI) was calculated; expressions of PPAR-γ and Glut-4 mRNA in skeletal muscle tissue were detected by reverse transcription polymerase chain reaction (RT-PCR). Results: Compared with normal diet group, body weight significantly increased in high fat diet group; body weight of HE group was significantly lower than that of high fat diet group (P<0.05). Compared with normal diet group, there were significant increase in FINS, FBG and IRI in high fat diet group and HE group (P<0.01). Compared with high fat diet group, there were significant decrease in FINS [(14.00±7.12) mmol/L vs. (10.17±3.88) mmol/L], FBG [(9.49±1.28) mmol/L vs. (8.03±1.67) mmol/L] and IRI [(1.47±0.38) vs. (1.06±0.27), P<0.05 all], and significant increase in expressions of PPAR-γ [(0.95±0.17) vs. (2.37±0.41)] and Glut-4 mRNA [(0.68±0.24) vs. (1.54±0.28), P<0.01 both] in HE group. Conclusions: Exercise may significantly improve insulin resistance, and the mechanism may be related with upregulation of expressions of PPAR-γ and Glut-4 mRNA in skeletal muscle, regulation of glucose metabolism and promotion of transduction of insulin signal.