Low-level laser irradiation, cyclooxygenase-2 (COX-2) expression and necrosis of random skin flaps in rats
Data
2012-05-01
Autores
Esteves Junior, Ivaldo 
Masson, Igor Bordello
Oshima, Celina Tizuko Fujiyama
Paiotti, Ana Paula Ribeiro
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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 x 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.
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Lasers in Medical Science. London: Springer London Ltd, v. 27, n. 3, p. 655-660, 2012.