Department of Surgery, Division of Operative Technique and Experimental Surgery, Federal University of São Paulo - UNIFESP, São Paulo, SP, Brazil.
Lasers Med Sci. 2012 May;27(3):655-60. doi: 10.1007/s10103-011-1011-1. Epub 2011 Oct 21.
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.
皮瓣仍然是外科医生关注的问题，因为皮瓣可能会失败导致坏死。然而，低水平激光照射已被报道为一种提高缺血皮瓣存活率的有效工具，但作用机制尚不清楚。我们研究了低水平激光照射对大鼠随意皮瓣存活率的影响，并测定了皮瓣蒂部 COX-2 的表达。研究动物包括 24 只 EPM-1 Wistar 大鼠，随机分为三组。所有动物均制作 10×4cm 颅顶背部随意皮瓣。一组进行激光模拟照射（假照射组），另外两组在术后即刻于皮瓣的颅顶侧 12 点用 0.29J 照射，能量密度 10.36J/cm2，辐照度 0.71W/cm2，或用 7.3J 照射，能量密度 260.7J/cm2，辐照度 3.57W/cm2。术后立即对皮瓣的颅顶侧进行上述处理，术后第 2 和第 5 天重复照射。术后第 7 天采用纸模板法测定皮瓣的坏死面积百分比。免疫组化法检测 COX-2 的表达，评分 0-3 分。与假照射组和 0.29J 照射组相比，7.3J 照射组的皮瓣坏死面积更小（P<0.05）；假照射组和 0.29J 照射组之间无差异。7.3J 照射组 COX-2 的表达低于假照射组和 0.29J 照射组（P<0.001）。用 7.3J 每点的激光能量对大鼠随意皮瓣进行低水平激光治疗可有效减少皮瓣坏死。激光照射还降低了皮瓣蒂部 COX-2 的表达。
