Carbon Dioxide-rich Water Bathing Increases Myonuclear Number and Muscle Fiber Size in Regenerating Skeletal Muscles

抄録

[Purpose] The purpose of this study was to investigate whether CO₂ water bathing accelerates skeletal muscle regeneration after injury. [Subjects] Wistar female rats (n=4/ each group) were used in this study.[Methods] The rats were divided into non-injury (NI), injury (IC), injury + tap water bathing (ITW), and injury + CO₂ water bathing (ICO₂) groups. Skeletal muscle injury was induced by injection of bupivacaine hydrochloride in left tibial anterior (TA) muscles. Tap and CO₂ water (1,000 ppm) bathing was performed at 37 °C for 30 minutes once a day. Left TA muscles in all groups were removed at 2 weeks after injury, and then myonuclear number, myofiber size, and the expression of MyoD and myogenin were measured. [Results] Myonuclear number was increased in the ICO₂ group compared with the IC and ITW groups. Myofiber size in the IC, ITW, and ICO₂ groups was smaller than in the NI group, but it was larger in the ICO₂ group than in the IC group. The levels of expression of MyoD and myogenin were the same in all groups. [Conclusion] CO₂ water bathing may accelerate skeletal muscle repair after injury.