Effects of hyperbaric exposure with high oxygen concentration on glucose and insulin levels and skeletal muscle‐fiber properties in diabetic rats

Abstract

The effects of hyperbaric exposure with high oxygen concentration on glucose and insulin levels and skeletal muscle-fiber properties were investigated in type 2 diabetic Goto-Kakizaki rats. Five-week-old rats were exposed to a hyperbaric environment (1.25 atmospheric pressure) with a high oxygen concentration (36%) for 6 h daily. Glucose and insulin levels and properties including fiber-type distribution, cross-sectional area, and oxidative enzyme activity in the soleus muscle were examined after hyperbaric exposure for 4 weeks. The growth-related increase in glucose level was inhibited by hyperbaric exposure, and insulin also showed lower levels compared with control rats. The percentage of low-oxidative type I fibers in the muscle decreased and high-oxidative type IIA and type IIC fibers, which were not detected in the muscle of control rats, were observed after hyperbaric exposure. The oxidative enzyme activity of type I fibers in the muscle increased after hyperbaric exposure. Hyperbaric exposure with high oxygen concentration might therefore provide a new approach to improve the glucose tolerance, insulin resistance, and altered skeletal muscle metabolism that are caused by diabetes mellitus. Muscle Nerve, 2006.

Long-term treatment with hyperbaric air improves hyperlipidemia of db/db mice

“…Different from the results of previous studies showing that HBO had an effect on glucose metabolism (12)(13)(14)(15), HBA treatment did not influence glucose metabolism in our experiments ( Figure 2A, 2B and not shown). Tissue hypoxia (38,39) and TNFα (40) or MCP-1 (41) induce insulin resistance, and high pressure up-regulates glycolytic genes (31).…”

“…In previous studies, HBO treatment could decrease blood glucose levels in humans (12) and rat (13,14), but investigations with HBO were not done for hyperlipidemia. In addition, the effects of HBA on diabetes and hyperlipidemia have not been studied, either.…”

“…It has been reported that levels of blood glucose in patients with hypertension and type 2 diabetes were significantly lowered by exposure to HBO (12). In animal experiments, HBO treatment prevented an increase in blood glucose level during growth and changed the muscle type to slow twitch subtype (13)(14)(15). On the other hand, HBO treatment significantly increased blood glucose levels in type 1 diabetic rats compared with the levels in non-diabetic controls (16).…”

Hyperbaric Exposure with High Oxygen Concentration Improves Altered Fiber Types in the Plantaris Muscle of Diabetic Goto-Kakizaki Rats

“…An interesting finding in our previous studies [8,17] was that the growth-related increase in the glucose level of diabetic rats was completely inhibited by hyperbaric exposure with high oxygen concentration. Furthermore, the insulin level of diabetic rats decreased after hyperbaric exposure with high oxygen concentration [8].…”

“…Therefore, altered patterns of fiber types in skeletal muscles may be linked to impaired glucose tolerance and insulin resistance. Our previous study [8] showed that the decreased percentage of high-oxidative fibers in the slow soleus muscle of Goto-Kakizaki rats shifted toward normal, which is observed in age-matched nondiabetic rats, after hyperbaric exposure with high oxygen concentration. In this study, we examined whether similar effects on the fiber type distribution and oxidative enzyme activity in the fast plantaris muscle of Goto-Kakizaki rats were observed after hyperbaric exposure with high oxygen concentration.…”