Salivary 8-OHdG Induction by Physical Exercise Training Under Food Restriction

OBJECTIVE We previously reported that physical exercise under food restriction induced alterations in saliva secretion, including a decrease in salivary kallikrein activity, while exercise training alone did not affect the overall saliva content. The objective of the present study was to examine the involvement of oxidative stress in alterations of salivary secretion due to physical exercise under food restriction. METHODS Male ICR mice at 32 weeks of age weighing from 39 to 50 g were divided into three groups: an exercise group with food restriction (EXP), an exercise group without food restriction (EXA) and a control group (CTL). The EXP group was fed the same amount of diet as the CTL group (pair-feeding). The EXP and EXA groups had access to a "voluntary running wheel" for exercise. The pilocarpine-stimulated whole saliva was collected from the oral cavity by micro-pipette over 15 min for 12 weeks after the beginning of the experiment. The salivary and serum 8-Hydroxy-2'-deoxyguanosine (8-OHdG) were determined. RESULTS The salivary 8-OHdG levels in the EXP group were significantly higher than in the CTL and EXA groups (p<0.01). CONCLUSION The alterations of salivary secretion in mice undergoing chronic exercise training under a food-restricted diet may occur as a result of oxidative stress.