Attenuation of Age-Dependent Lipid Profile by Treadmill Running in Different Skeletal Muscle Fibers of Old Rats

The goal of this study was to distinguish the impact of regular treadmill running on age-induced altered lipid profiles in different skeletal muscle fiber types of rats. Wistar strain male albino rats of two age groups, young (3 months, n = 12) and aged/old (18 months, n = 12) were divided into two groups such as, control (Con) and exercise trained (ExT; 23 m/min, 30 min/day, 5 days/week for 12-week). After completion of the last training session, lipid metabolic profiles, including total cholesterol (TC), triglycerides (TG), phospholipids and malondialdehyde (MDA, lipid peroxidation marker) levels were monitored in soleus (SOL), red gastrocnemius (RG) and white gastrocnemius (WG) muscle fibers of rat. The TC, TG and MDA contents were significantly (P ＜ 0.05) increased with advancement of age, while, phospholipid content was decreased with age in all muscle fiber types. However, here we found significantly (P ＜ 0.05) decreased TC and TG levels, and increased phospholipid contents after treadmill exercise in all muscle fiber types of aged rats. The decreased TC content was more in young muscles (WG 31%), and the increased phospholipid content was more in old muscles fibers after treadmill running compared to their respective counter age group rats. However, increased MDA levels in old muscle fibers (SOL-132.13 ±2, RG-129 ±2 and WG-147 ±2.5 μmoles/g) were not attenuated by exercise training (SOL- 151 ±2.4, RG-148 ±2.7 and WG-157 ±3 μmoles/g) in this study. These results demonstrated that decreased TC and TG, and increased phospholipid contents by regular treadmill running might be beneficial to counteract the age-associated malfunctions in different muscle fiber types and also avoid the musculoskeletal disorders in aged rats.