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

Abstract

Hyperbaric exposure with high oxygen concentration inhibits a growth-related increase in the glucose and insulin of diabetic rats. In this study, 5-week-old diabetic Goto-Kakizaki rats were exposed to a hyperbaric environment (1.25 atmospheric pressure) with a high oxygen concentration (36%) for 6 h daily. Fiber type distributions and oxidative enzyme activities in the fast-twitch plantaris muscle of Goto-Kakizaki rats were examined after hyperbaric exposure for 4 weeks. The percentages of high-oxidative type I and type IIA fibers increased and that of low-oxidative type IIB fibers decreased after hyperbaric exposure. Furthermore, the fiber oxidative enzyme activity increased after hyperbaric exposure, regardless of fiber type. It is concluded that altered patterns of fiber types in the plantaris muscle of diabetic rats shift toward normal, which is observed in nondiabetic rats, following hyperbaric exposure with high oxygen concentration.Key words: diabetes mellitus, hyperbaric oxygenation, plantaris muscle.Patients and animal models with type 2 diabetes mellitus exhibit altered patterns of fiber types in skeletal muscles [1][2][3][4][5]. Goto-Kakizaki rats, animal models of spontaneous type 2 diabetes mellitus [6], have a lower percentage of high-oxidative fibers in the slow soleus and fast plantaris muscles than age-matched nondiabetic rats [7]. 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. Materials and methodsFive-week-old male Wistar (n = 10) or Goto-Kakizaki (n = 10) rats were randomly assigned to the control (n = 5) or hyperbaric (n = 5) groups. All rats were individually housed in cages of the same size. The rats in the hyperbaric group were exposed to an atmospheric pressure of 1.25with an oxygen concentration of 36% automatically maintained by a computer-assisted system in a hyperbaric chamber [9]. They were exposed to the hyperbaric environment for 6 hours (10:00 to 16:00) daily for 4 weeks. Food and water were provided ad libitum for all groups. All rats were kept in a controlled environment with fixed 12:12 h light:dark cycles (lights off from 19:00 to 07:00) and room temperature maintained at 22 ± 2°C. All procedures were approved by our institutional review committee and followed the guidelines of the Physiological Society of Japan for the care and use of experimental animals.The rats were weighed and anesthetized with an intraperitoneal injection of sodium pentobarbital (50 mg/kg body weight). After blood sampli...

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).…”

“…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).…”

Effects of exposure to hyperbaric oxygen on oxidative stress in rats with type II collagen-induced arthritis

“…Previously, we reported that the beneficial effects of hyperbaric oxygen exposure with 36% oxygen concentration at 1.25 ATA were associated with an increased oxidative enzyme activity in skeletal muscle fibers and spinal motoneurons in rats [7,8]. In addition, the possible beneficial effects of exposure to hyperbaric oxygen have been reported; the increase in blood glucose level, which is related to growth, of type 2 diabetic rats has been reported to be inhibited by exposure to hyperbaric oxygen [38][39][40]. We observed that the levels of dROMs decreased in arthritic rats following exposure to hyperbaric oxygen (Fig.…”

Hyperbaric Oxygen Exposure Improves Blood Glucose Level and Muscle Oxidative Capacity in Rats with Type 2 Diabetes

“…In fact, exposure to hyperbaric oxygen inhibited both the growth-related transition of fiber types from the high-oxidative to the low-oxidative and the decrease in fiber oxidative enzyme activity in the soleus and plantaris muscles of GK rats. 7,8 In this study, we aimed to clarify whether exposure to hyperbaric oxygen reduces high blood glucose levels in rats with type 2 diabetes and whether these effects are maintained under normobaric conditions even after exposure to hyperbaric oxygen. We observed that exposure to hyperbaric oxygen reduced the high blood glucose level in rats with type 2 diabetes and that this effect was maintained after exposure to hyperbaric oxygen (Fig.…”

“…6 Furthermore, it inhibits both the transition of fiber types from the high-oxidative to the low-oxidative and the decrease in fiber oxidative enzyme activity in the soleus and plantaris muscles of rats with type 2 diabetes. 7,8 However, there is no evidence to clarify whether exposure to hyperbaric oxygen reduces high blood glucose levels in rats with type 2 diabetes or whether these effects are maintained under normobaric conditions even after exposure to hyperbaric oxygen.…”