Assessment of the behavior of myofibroblasts on scalpel and CO(2) laser wounds: an immunohistochemical study in rats.
OBJECTIVE
The aims of this study were to quantitative and statistically assess the presence of myofibroblasts on both conventional and CO(2) laser wounds.


BACKGROUND
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 CO(2) laser wounds.


METHODS
Thirty-two animals (rattus norvegicus) were divided into four groups and treated using either the CO(2 )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 alpha-smooth muscle actin (alpha SMA) and analyzed under light microscopy (40x) 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).


CONCLUSIONS
It is concluded that the small number of myofibroblasts at day eight after wounding with the CO(2) laser may be the reason that contraction on this wound is smaller than the one observed in conventional surgery.
Faculdade de Odontologia, Universidade Federal da Bahia, Canela, Salvador, Brazil.
André Carlos
AC
de Freitas
Antonio Luiz B
AL
Pinheiro
Marilia Gerardt
MG
de Oliveira
Luciana Maria Pedreira
LM
Ramalho
D000818:Animals; D003239:Connective Tissue Cells / Q000502:physiology; D005347:Fibroblasts / Q000502:physiology*; D006097:Granulation Tissue / Q000166:cytology; D053685:Laser Therapy; D008297:Male; D009132:Muscles / Q000166:cytology*; D051381:Rats; D017208:Rats, Wistar; D014945:Wound Healing / Q000502:physiology*