Influence of low level laser therapy on wound healing and its biological action upon myofibroblasts.
OBJECTIVE
In re-evaluating the effects of laser therapy in wound healing, the role of extracellular matrix elements and myofibroblasts, was analyzed.


METHODS
Cutaneous wounds were inflicted on the back of 72 Wistar rats. Low level laser was locally applied with different energy densities. Lesions were analyzed after 24, 48, 72 hours and 5, 7, and 14 days. Tissues were studied by histology, immunohistochemistry, and electron microscopy.


RESULTS
In treated animals, the extent of edema and the number of inflammatory cells were reduced (P < 0.05), but the amount of collagen and elastic fibers appeared slightly increased. Desmin/smooth muscle alpha-actin-phenotype myofibroblasts were statistically more prominent on the 3rd day after surgery (P < 0.05) in treated wounds than in controls. Treatment with a dosage of 4 J/cm(2) was superior to that with 8 J/cm(2).


CONCLUSIONS
Laser therapy reduced the inflammatory reaction, induced increased collagen deposition and a greater proliferation of myofibroblasts in experimental cutaneous wounds.
Medrado
Alena R A P
AR
Laboratory of Experimental Pathology, Oswaldo Cruz Foundation-Salvador, Bahia, Brazil. alenamedrado@hotmail.com
Pugliese
Lívia S
LS
Reis
Sílvia Regina A
SR
Andrade
Zilton A
ZA
D000704:Analysis of Variance; D000818:Animals; D001707:Biopsy, Needle; D004195:Disease Models, Animal; D005260:Female; D005347:Fibroblasts / Q000473:pathology / Q000528:radiation effects; D007150:Immunohistochemistry; D028022:Low-Level Light Therapy / Q000379:methods*; D008297:Male; D032446:Myoblasts / Q000473:pathology / Q000528:radiation effects; D011336:Probability; D051381:Rats; D017208:Rats, Wistar; D012016:Reference Values; D012680:Sensitivity and Specificity; D012867:Skin / Q000473:pathology / Q000528:radiation effects; D016896:Treatment Outcome; D014945:Wound Healing / Q000502:physiology / Q000528:radiation effects*; D014947:Wounds and Injuries / Q000473:pathology* / Q000532:radiotherapy*