The Impact of 12 Weeks of High-Intensity Interval Training on Fibrosis Markers in the Visceral Adipose Tissue of Rats Fed a High-Fat and High-Carbohydrate Diet

Obesity is characterized by an excessive accumulation of adipose tissue, accompanied by inflammation and fibrosis, and exercise is recognized as an effective intervention against it. Consequently, the present study aimed to investigate the effects of high-intensity interval training (HIIT) on the expression levels of PEDP and MMP14 proteins in the visceral adipose tissue of rat fed a high-fat and high-carbohydrate diet (HFD+HC).

For this purpose, twenty-four Sprague-Dawley rats were randomly divided into three groups of eight, consisting of a standard diet (ND), HFD+HC, and HFD+HC+HIIT. The HIIT group ran on a treadmill with a training regimen that included 7 intervals of 4 mins at 90-85% of maximum speed (Vmax), interspersed with 2-min rest intervals at 50% of Vmax. Following this, visceral adipose tissue was extracted for the assessment of PEDP and MMP14 protein expression using the Western blot technique. Statistical analysis was performed using ANOVA and Tukey's post hoc tests, with significance set at p< 0.05.

The HFD+HC group showed a significant decrease (p=0.002) in PEDP protein expression and a significant increase (p=0.01) in MMP14 expression. Conversely, HIIT resulted in a significant increase (p=0.03) in PEDP and a non-significant decrease (p=0.26) in MMP14 expression.

Obesity leads to reduced anti-fibrotic proteins and increased fibrotic factors in visceral adipose tissue. In contrast, HIIT during HFD+HC significantly enhances anti-fibrotic protein expression and moderately decreases fibrotic protein expression. These changes may help mitigate adipose tissue dysfunction (fibrosis) induced by HFD+HC, likely reducing inflammation and insulin resistance.