[ effect of obesity and endurance training-induced weight loss on UCP3 mRNA expression in C57BL/6 MICE]

ABSTRACT

The purpose of this study was evaluating the effect of obesity and weight reduction induced by endurance training on UCP3 mRNA expression in C57BL/6 mice. Twenty-four C57BL/6 mice consumed a high-fat diet, while 6 [NB Group] were fed a normal chow for 12 weeks. After the fattening period, 6 obese mice [OB Group] were sacrificed. Twelve mice trained 5 sessions per week for 12 weeks on a rodent treadmill with high [HI Group] [75% VO2max] and/or low intensity [LI Group] [50% VO2max] during a training period. The control group [OC Group] was kept inactive in the cages till the end of the period. Body weight was measured and recorded weekly. UCP3 mRNA expression was measured in gastrocnemius muscle using Real Time-PCR method and plasma FFA concentrations were measured using the ELISA method. In the training groups, weight reduction was significant in the 8th week [p<0.05]. Average relative UCP3 mRNA expression was significantly lower in the HI and LI groups, than in the OC group [0.5 +/- 0.25 and 1.04 +/- 0.96, respectively, vs. 2.58 +/- 0.57 arbitrary unit; p<0.05]. Plasma FFA concentrations were significantly lower in the HI and OB groups compared to the LI group [p<0.05]. When energy intake and consequently body weight increases, UCP3 increases to extend the thermogenesis and fatty acid oxidation's process. In contrast, UCP3 downregulates with exercise-induced weight loss in order to counteract this process