Mild hyperbaric oxygen inhibits growth-related decrease in muscle oxidative capacity of rats with metabolic syndrome

Aim: we examined the effects of mild hyperbaric oxygen on the properties of the soleus muscle in rats with metabolic syndrome. methods: five-week-old metabolic syndrome (shr/ndmcr-cp,cp/cp) rats were divided into normobaric (cp) and mild hyperbaric oxygen (cp-h) groups (n=5/group). in addition,5-week-old wistar rats were assigned as the normobaric control (wr) group (n= 5). the cp-h group was exposed to 1.25 atmospheres absolute with 36% oxygen for 3 h daily for 16 weeks. succinate dehydrogenase (sdh) activity and mrna levels of peroxisome proliferator-activated receptor γ coactivator-1α (pgc-1α) in the soleus muscle were examined. the fiber type composition,cross-sectional areas,and sdh staining intensity in the soleus muscle were also examined. results: the cp-h group showed lower fasting and nonfasting blood glucose,glycated hemoglobin,total cholesterol,triglyceride,insulin,and systolic blood pressure levels; higher adiponectin levels; and higher sdh activity and mrna levels of pgc-1α in the muscle than the cp group. compared with the cp group,the cp-h group had a lower percentage of type i fibers and observed type ii a fibers in the muscle. the cp-h group also had higher sdh staining intensity of type i and type ii c fibers in the muscle than the cp group. no differences in these values were observed in the muscles of the wr and cp-h groups. conclusion: mild hyperbaric oxygen inhibited growth-related increase in blood glucose levels and decrease in muscle oxidative capacity of rats with metabolic syndrome because of improved oxidative metabolism. © 2017 japan atherosclerosis society.