Dose-dependency of Low-energy HeNe Laser Effect in Regeneration of Skeletal Muscle in Mice

Abstract

. We evaluated the effect on mice skeletal muscle regeneration of different doses (2.6, 8.4, and 25 J/cm²) of HeNe laser (λ 632.8 nm; power, 2.6 mW; spot size, 0.007 cm²) applied directly to intact skin of injured muscle. Muscle injury was induced in both right and left Tibialis anterior (TA) muscles by ACL myotoxin (5 mg/kg). Right TA muscles were irradiated daily for 5 days while contralateral muscles received a sham treatment. Only the 2.6 J/cm² dose resulted in changes such as increased mitochondrial density and muscle fibre in the TA muscles as compared to sham groups (3280±704 µm² versus 2110±657 µm², p=0.02). We concluded that the HeNe effect on mouse muscle regeneration is dose-specific: only 2.6 J/cm² increased muscle fibre area and mitochondrial density.