Low-level laser irradiation, cyclooxygenase-2 (COX-2) expression and necrosis of random skin flaps in rats.
Skin flaps are still a matter of concern among surgeons, as failures can occur leading to flap necrosis. However, low-level laser irradiation has been reported as an effective tool to improve the viability of ischemic flaps, yet its mechanisms of action remain unclear. We investigated the effect of low-level laser irradiation on the viability of random skin flaps in rats and determined COX-2 expression in the flap pedicle. The study animals comprised 24 EPM-1 Wistar rats which were randomly allocated into three equal groups. A cranially based dorsal random skin flap measuring 10 × 4 cm was created in all the animals. In one group, laser irradiation was simulated (sham group), and in the other two groups the animals were irradiated at 12 points with 0.29 J at 20 mW (energy density 10.36 J/cm(2), irradiance 0.71 W/cm(2)), or with 7.3 J at 100 mW (energy density 260.7 J/cm(2), irradiance 3.57 W/cm(2)). These procedures were applied to the cranial half of the flap immediately after surgery and were repeated on days 2 and 5 after surgery. The percentage necrotic area was determined on day 7 after surgery by the paper template method. The immunohistochemical expression of COX-2 in the samples was given scores from 0 to 3. The necrotic area was smaller in group irradiated at 7.3 J compared to sham-treated group and to the group irradiated at 0.29 J (P < 0.05); there was no difference between the sham-treated group and group irradiated at 0.29 J. COX-2 expression was lower in the group irradiated at 7.3 J than in the sham-treated group and the group irradiated at 0.29 J (P < 0.001). Low-level laser therapy was effective in decreasing random skin flap necrosis in rats using a laser energy of 7.30 J per point. Laser irradiation also decreased the expression of COX-2 in the flap pedicle.
Department of Surgery, Division of Operative Technique and Experimental Surgery, Federal University of São Paulo - UNIFESP, São Paulo, SP, Brazil.
Ivaldo
I
Esteves Junior
Igor B
IB
Masson
Celina T F
CT
Oshima
Ana Paula R
AP
Paiotti
Richard E
RE
Liebano
Helio
H
Plapler
D000818:Animals; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D007150:Immunohistochemistry; D007249:Inflammation / Q000517:prevention & control; D054023:Lasers, Semiconductor / Q000627:therapeutic use; D028022:Low-Level Light Therapy; D008297:Male; D009336:Necrosis; D051381:Rats; D017208:Rats, Wistar; D012867:Skin / Q000201:enzymology / Q000473:pathology / Q000528:radiation effects; D013524:Surgical Flaps / Q000009:adverse effects / Q000473:pathology / Q000502:physiology
D051546:Cyclooxygenase 2; C489691:Ptgs2 protein, rat