Mild hyperbaric oxygen enhanced the regeneration of the tibialis anterior muscle after the cardiotoxin-induced muscle injury

Skeletal muscle injuries are widespread in everyday life and sports. The purpose of the present study was to determine whether exposure to mild hyperbaric oxygen (MHO) after muscle injury accelerates recovery. Male 8-week-old mice were injected with 30 μL of 10 μM cardiotoxin (CTX) into the left tibialis anterior (TA) muscle and saline into the right TA muscle. The mice were then divided into a normal control (CON) and an MHO (1.3 atm with 38% oxygen) group. Four weeks after CTX injection, cross-sectional area (CSA) was higher in the CTX + MHO group than in the other groups (P < 0.05). The number of centrally nucleated fibers (%) was 11.5% lower in the CTX + MHO group than in the CTX + CON group (P < 0.05), while it was higher in the CTX groups than in the saline groups regardless of MHO exposure (P < 0.05). MHO exposure had a negative main effect on the number of Pax7-positive nuclei (P < 0.05). MHO accelerated muscle recovery, characterized by a reduced proportion of centrally nucleated fibers and increased cross-sectional area of regenerating muscle fibers.