Effect of Concurrent High-intensity Interval Training and a Period of High-fat Diet on Col6A3 Gene Expression and Its Protein Product in Subcutaneous Adipose Tissue and Rats

Collagen 6 is one of the important components of the adipose tissue extracellular matrix, and its deposition is associated with metabolic disorders. This study aimed to investigate the effect of High-intensity Interval Training (HIIT) simultaneously with a high-fat diet on the expression of collagen 6 chain 3 alpha gene (Col6A3) and the amount of its protein product (COL6α3) in subcutaneous adipose tissue, as well as insulin resistance in rats.

Twenty-four adult male rats were randomly divided into four groups: normal diet (ND), high-fat diet (HFD), HIIT+ND, and HIIT+HFD. The HIIT consisted of eight periods of intense activity at 90% of Maximum Running Capacity (MRC) for 2.5 minutes, with periods of active rest at 50% MRC for 2.5 minutes. Blood samples were collected from the heart 48 hours after the last training session, and the subcutaneous adipose tissue was removed. Serum glucose and insulin levels were measured, and insulin resistance (HOMA-IR) was calculated. The RT-PCR and ELISA methods were used to measure gene expression and COL6α3 tissue protein levels, respectively. Two-way ANOVA and correlation coefficient were used to analyze the data (P≤0.05).

The combination of HIIT and a high-fat diet caused a significant decrease in COL6α3 gene expression and tissue protein levels (P<0.001) and a 21% decrease in HOMA-IR (P<0.001). A significant positive correlation was observed between gene expression and COL6α3 protein level and HOMA-IR (P<0.001) (r=0.794, r=0.870).  

HIIT, simultaneously with consuming a high-fat diet, prevents the increase of COL6α3 in subcutaneous fat tissue and can have a preventive effect on insulin resistance.