Differential expression of myofibroblasts on C02 Laser wounds and scalpel wounds: an experimental model

摘要

Wound contraction of both traumatic and surgical origin may reduce or limit the function of the tissue. Myofibroblasts are cells involved on the process of wound contraction, which is smaller on CO_2 Laser wounds. The aims of this study were to quantitative and statistically assess the presence of myofibroblasts on both conventional and CO_2 Laser wounds. Thirty-two animals (rattus norvegicus) were divided into four groups and operated using either the CO_2 Laser (groups Al and A2) or conventional scalpel (groups B1 and B2). The animals were sacrificed eight days post-operatively (groups: Al and Bl) and 14~(th) days after surgery (groups: A2 and B2). The spec imens we re routinely processed to wax and stained with a-Smooth Muscle Actin (aSMA) and analyzed under light microscopy (40X). Two standard areas around the wound of each slide were selected and used to count the number of myofribroblasts present using a calibrated eyepiece and a graticule. The number of myofibroblasts at day eight was significantly higher than at day 14~(Th). Comparison of the two techniques at day eight showed significant differences between the two groups (Laser, p=0.007 and scalpel, p=0.001). The number of cells present on group Bl was significantly higher than group Al (p=0.001). However at the 14~(th) day there was no such difference (p=0,072). It is concluded that the small number of myofibroblasts at day eight after wounding with the CO_2 Lasermay be the reason why contraction on this wound is smaller than the one observed in conventional surgery.