This study investigated the effects of exposure to mild hyperbaric oxygen during unloading on the properties of the soleus muscle in rats, because exposure to mild hyperbaric oxygen enhances oxidative metabolism in cells and tissues. Therefore, exposure to mild hyperbaric oxygen should inhibit the unloading-induced degenerative changes in skeletal muscles. One group of 7-week-old male Wistar rats were unloaded by hindlimb suspension for 2 weeks (HU, n = 12). A second group of age-matched rats were exposed to mild hyperbaric oxygen at 1317 hPa with 40% oxygen for 3 h a day during hindlimb suspension (HU + MHO, n = 12). A third group of age-matched rats without hindlimb suspension and exposure to mild hyperbaric oxygen were assigned as the controls (WR, n = 12). Soleus muscle weight (per body weight), succinate dehydrogenase (SDH) activity, and peroxisome proliferator-activated receptor γ coactivator-1α (Pgc-1α) mRNA levels were lower in the HU and HU + MHO groups than in the WR group, and these were higher in the HU + MHO group than in the HU group. The unloading-induced type shift from type I to type IIA fibers was inhibited by exposure to mild hyperbaric oxygen during unloading. It is concluded that the unloading-induced decrease in soleus muscle weight (per body weight) and type shift from type I to type IIA fibers in the soleus muscle were partially inhibited by exposure to mild hyperbaric oxygen during unloading.

中文翻译：

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卸载过程中暴露于轻度高压氧对大鼠肌肉特性的影响。

这项研究调查了在卸载过程中暴露于轻度高压氧对大鼠比目鱼肌特性的影响，因为暴露于轻度高压氧会增强细胞和组织的氧化代谢。因此，暴露于轻度高压氧应抑制骨骼肌卸载引起的退行性改变。一组7周大的雄性Wistar大鼠通过后肢悬吊卸载2周（HU，n  = 12）。第二组年龄匹配的大鼠在后肢悬吊期间（HU + MHO，n  = 12）在1317 hPa和40％的氧气下暴露于轻度高压氧3天。第三组年龄匹配的大鼠没有后肢悬吊并暴露于轻度高压氧作为对照组（WR，n = 12）。HU和HU + MHO组的比目鱼肌重量（每体重），琥珀酸脱氢酶（SDH）活性和过氧化物酶体增殖物激活的受体γ共激活因子1α（Pgc - 1α）mRNA水平低于WR组，并且在HU + MHO组中，这些比例高于在HU组中。在卸载过程中，暴露于轻度的高压氧气可抑制由卸载引起的从I型到IIA型纤维的类型转变。结论是，在卸载过程中，暴露于轻度的高压氧会部分抑制由卸载引起的比目鱼肌重量（每体重）的减少以及比目鱼肌从I型到IIA型纤维的类型转移。