Effects Of Low Energy Laser On Regeneration After Skeletal Muscle Contusion In Rats

Low energy laser theary(LLLT) is a category of therapeutic laser which can initiate certain photostimulation effects but not thermal effects on biological tissues, resulting some biological changes.Low energy laser therapy has some excellence such as safety,convenience,low cost,et at.currently LLLT has been accepted worldwide for clinical use,including in Canada,Mexica,the United Kingdom,Spain.The effects of LLLT on skeletal muscle injury have been noted for a long time,but the mechanism is not very clear.Aims of studyWe investigated the effects of 635nm GaAlAs laser(which was made in U.S.and approved by FDA) on muscle contusion in rats by histological,biochemical,molecular biology techniques.Method96 Sprague-Dawley rats with body weight of 180～220g were randomly allocated to 2 groups,the control group(6) and experimental groups(90).The experimental groups were allocated to natural healing group and LLLT groups.According to the time of samples being taken,the natural healing groups were further allocated to right after injury,1,2,3,7,14,21,28d after injury groups,and the LLLT groups were allocated to 1,2,3,7,14,21,28d after injury groups.The injuried muscle of the LLLT groups were irradiated by Erchonia EML(ML2) laser made in U.S.A.,wavelength 635nm,incident power 7m W,irradiated area 0.4cm~2, power density 17.5mW/cm~2,irradiated time 20min,period of treatment 10d.At right after injury,1d,2d,3d,7d,14d,21d,28d after injury,the rats were killed and the blood,the muscle were disposed and kept for the following histological, biochemical,immunohistobiochemistry and molecular biological experiments. Results1.The results of optics microscope and electronic microscope,plasma CK activity, gastrocnemius MHC-IIb mRNA revealed that,low energy GaAlAs laser can promote the regeneration after skeletal muscle injury,accelerate the healing process of histology, lessen the scar formation,improve the quality of the muscle.2.Low energy GaAlAs laser can improve SOD activity of the injuried muscle and the ability of anti oxidant,lessen the oxidative injury.3.Low energy GaAlAs laser can improve the expression of IGF-ⅠmRNA in injuried muscle significantly.4.Low energy GaAlAs laser can improve the expression of MHC-Ⅱb mRNA in injuried muscle significantly.5.Low energy GaAlAs laser can supress the expression of Collagen-Ⅰ,Collagen-ⅢmRNA in injuried muscle significantly.4.Low energy GaAlAs laser can improve proliferate activity of the skeletal satellite cell.Conclusions1.Low energy GaAlAs laser can promote the recovery of acute skeletal muscle contusion in rats.2.Low energy GaAlAs laser can promote the antioxidative activuty of the injuried muscel,lesesn the oxidative injury.3.Low energy GaAlAs laser can the satellite cell's proliferative activity and up-regulate the expression of IGF-ⅠmRNA in the injuried muscel.4.Low energy GaAlAs laser can down-regulate the expression of callagen-Ⅰ, callagen-ⅢmRNA in the injuried muscle,and lessen the scar formation.