The Effect of GaAlAs Laser Irradiation on VEGF Expression in Muscle Contusion of Rats

GaAlAs 레이저 조사가 근타박상이 유발된 흰쥐 골격근내 혈관내피성장인자 발현에 미치는 영향

Skeletal muscle regeneration is a vital process for various muscle myopathies and muscular adaptation to physiological overload. Angiogenesis is the key event in the process of muscle regeneration, and vascular endothelial growth factor(VEGF) plays an important role in it. The purpose of this study was to evaluate the effect of GaAlAs(830nm) laser and immunoreactivity of VEGF on angiogenesis after muscle contusion injury. Muscle contusion injury was induced in the triceps surae muscle by dropping a metal bead(31.4g). GaAlAs laser irradiation(power 20 mW, frequency 2000 Hz, treatment time 15 min) was applied directly to the skin of injured muscle daily for seven days. The experimental group I was irradiated immediately by laser after injury, whereas the experimental group II was irradiated after 1 day of injury. The control group was non-irradiated. The results of this study were as follows. 1. In morphological observation, there were no significant changes in experimental and control groups for 7 days. At 3 days, however, the splited muscle fibers were observed in experimental groups, and the muscle atrophy and granular tissue viewed at 7 days in control group. 2. The VEGF was expressed in muscle fiber that located in the interspace between gastrocnemius and soleus muscles. As the time coursed, the immunoreactivity of VEGF also seemed to be strong in the individual muscle fibers. 3. The experimental group I & II showed higher immunoreactivity of VEGF than control group(p<0.05). Then, the experimental group I showed higher than group II especially(p<0.05). These data suggest GaAlAs semiconduct diode laser irradiation(830nm) enhanced angiogenesis in the skeletal muscle induced contusion injury, and immediate laser irradiation after injury promoted the angiogenesis greatly than after 1 day of injury.