Analysis of lipid composition in muscle tissue of obese and lean rats.

Abstract

Skeletal muscle is a complex component of the body and muscle contraction has significant implications for caloric expenditure. Lipid metabolism is defined as the production and breakdown of different lipids in the body for metabolic demands. Skeletal muscle plays an important role in lipid metabolism. Obesity and other metabolic diseases are characterized by fatty acid accumulation in the form of triglycerides and cholesterol esters. Furthermore, muscle tissue is vulnerable to lipid composition alterations. Here we used tissue from rats bred for high endurance capacity (HCR) and rats bred for low endurance capacity (LCR). It is well known that HCR rats have better metabolic health than LCR rats, who are more prone to metabolicillnesses. To what extent this arises from differences in lipid composition in the two models is unknown. We used these models to investigate the influence of aerobic fitness on global lipid composition in rat skeletal muscle. The lipids were extracted from the HCR and LCR muscle tissue and characterized using thin layer chromatography to separate and differentiate lipid classes in the rat tissue. We hypothesize that there will be a larger content of free fatty acids, triglycerides, and ceramides in LCR compared to HCR models, potentially contributing to a difference in performance and health of the HCR and LCR rats.