Assessment of the Behavior of Myofibroblasts on Scalpel and CO 2 Laser Wounds: An Immunohistochemical Study in Rats

Abstract

Objective: The aims of this study were to quantitative and statistically assess the presence of myofibroblasts on both conventional and CO₂ laser wounds. Background Data: Wound contraction of both traumatic and surgical origin may reduce or limit the function of the tissue. Myofibroblasts are cells involved in the process of wound contraction, which is smaller in CO₂ laser wounds. Materials and Methods: Thirty-two animals (rattus norvegicus) were divided into four groups and treated using either the CO₂ laser (groups 1 and 2) or conventional scalpel (groups 3 and 4). The animals were sacrificed eight days post-operatively (groups: 1 and 3) and 14 days after surgery (groups: 2 and 4). The specimens were routinely processed to wax and stained with α-smooth muscle actin (αSMA) and analyzed under light microscopy (40×) using a calibrated eyepiece and a graticule. Two standard areas around the wound of each slide were selected and used to count the number of myofibroblasts present. Results: The results of this study show that it is possible to determine the number of myofibroblasts present in wounds produced by the laser or the scalpel at both eight and 14 days after surgery. However the number of myofibroblasts at day eight was significantly higher than at day 14 (laser, p = 0.007 and scalpel, p = 0.001). The number of cells present in group 3 was significantly higher than in group 1 (p = 0.001). However on the 14th day there was no such difference (p = 0.072). Conclusion: It is concluded that the small number of myofibroblasts at day eight after wounding with the CO₂ laser may be the reason that contraction on this wound is smaller than the one observed in conventional surgery.