Abstract
Mild hyperbaric oxygen (MHO) attenuates the muscle atrophy caused by muscle disuse. Training cessation results in the partial or complete loss of training-induced adaptations, including mitochondrial enzyme activities. The present study aimed to determine whether exposure to MHO after running training attenuated negative adaptation induced by detraining. We allocated eight-week-old mice into training (Tr), detraining after the training period (DeTr), and detraining + mild hyperbaric oxygen (DeTr + MHO, 1.3 atm absolute with 38 % oxygen) groups. Mice underwent voluntary wheel running for four weeks, followed by a two-week detraining period under normal or MHO conditions. The soleus muscle weight (mg/g BW) decreased by approximately 30 % in the DeTr and DeTr + MHO groups compared to the Tr group (P < 0.001 and 0.01, respectively). Citrate synthase (CS) activity, the expression of mitochondrial complex IV, antioxidant-related proteins, catalase, and heme oxygenase 1 (HO-1), decreased in the DeTr and DeTr + MHO group compared to the Tr group (P < 0.05). In summary, MHO did not attenuate the detraining-induced decrease in soleus muscle weight relative to body weight, mitochondrial enzyme activity, protein, or antioxidant protein expression level in the plantaris muscle after a four-week training period using voluntary wheel running in mice.