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 (lambda 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 microns 2 versus 2110 +/- 657 microns 2, 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.

Influence of Laser Therapy and Muscle Relaxant on the Masseter Muscle under Occlusal Wear: An Ultrastructural Study

“…There were no statistical differences between the experimental periods in this group. These findings are similar to previous studies that demonstrated beneficial action of the laser on muscular TMD (Shinozaki et al;Amaral & Salvini, 2001;Costardi et al, 2008;Farias, 2005;Frare & Nicolau, 2008). Despite the laser therapy role on muscle tissues, some authors have performed some studies.…”

Effects of GaAs laser and stretching on muscle contusion in rats

“…However, muscle fiber area is a better measurement than absolute muscle weight for the evaluation of skeletal muscle trophism and we found no difference in the muscle fiber across the section area. Other authors also observed no difference in the muscle weight of animals subjected to injury and treated with laser or just stretched 31,27 . Therefore, it can be suggested that the combination of the laser and stretching interferes differently in muscle mass, when compared to the isolated action of these resources, which require more investigation.…”

“…This outcome indicated that the muscle contusion induced with the apparatus did not prevent normal body weight gain of the animals, also observed by other authors 23 . However, Amaral et al 31 found no statistical difference in the body weight of animals subjected to muscle injury and myotoxin treated by laser. Coutinho et al 27 reported increased body weight in animals subjected to stretching in rat soleus muscle.…”

Efectos del Láser de Baja Intensidad (As-Ga-Al 904 nm) sobre el Cóndilo Mandibular de Conejos: Análisis a través de Tomografía Computadorizada Cone Beam

“…En relación a la dosis de radiación, existe gran diversidad de criterios respecto los parámetros de energía, potencia y tiempo que se debe utilizar. De acuerdo con algunos investigadores, dosis bajas producen un efecto de estimulación del metabolismo celular mientras que dosis altas producen efectos dañinos a la célula (Amaral et al, 2001;Houghton & Brown, 2000). Hawkins & Abrahamse (2006) señalan que la dosimetría (o fluencia) puede cambiar los procesos celulares.…”