Effects of exercise training on gingival oxidative stress in obese rats

Objective: The purpose of the present study was to investigate the effects of exercise training on serum reactive oxygen species (ROS) level and gingival oxidative stress in obese rats fed a high-fat diet. Design: Rats were divided into three groups (n = 14/group): one control group (fed a regular diet) and two experimental groups (fed a high-fat diet with and without exercise training [treadmill: 5 days/week]). The rats were sacrificed at 4 or 8 weeks. The level of serum reactive oxidative metabolites (ROM) was measured as an indicator of circulating ROS. The level of 8-hydroxydeoxyguanosine (8-OHdG) and reduced-form glutathione (GSH)/oxidised-form glutathione (GSSG) ratio were determined to evaluate gingival oxidative stress. Results: The obese rats fed a high-fat diet without exercise training showed higher serum ROM levels [Carratelli Units (CARR U)] (mean +/- SD; 413 +/- 64) than the control (333 +/- 12) at 4 weeks (p = 0.023). Such a condition resulted in higher 8-OHdG levels (ng/mg mtDNA) (0.97 +/- 0.18) (p < 0.05) and a lower GSH/GSSG ratio (17.0 +/- 3.1) (p < 0.05) in gingival tissues, compared to the control (0.55 +/- 0.13 for 8-OHdG and 23.6 +/- 5.8 for GSH/GSSG ratio) at 8 weeks. In addition, the obese rats fed a high-fat diet with exercise training showed lower serum ROM (623 +/- 103) (p<0.001) and gingival 8-OHdG levels (0.69 +/- 0.17) (p = 0.012) than those without exercise training (1105 95 for ROM and 0.55 +/- 0.13 for 8-OHdG) at 8 weeks. Conclusions: Obesity prevention by exercise training may effectively suppress gingival oxidative stress by decreasing serum ROS in rats.