Effect of low-level laser therapy on mast cells in viability of the transverse rectus abdominis musculocutaneous flap.

OBJECTIVE To assess the effect of low-level laser therapy (LLLT) on viability of mast cells of the transverse rectus abdominis musculocutaneous (TRAM) flap. BACKGROUND DATA LLLT has been recently used on the TRAM flap to stimulate mast cells. MATERIALS AND METHODS Eighty-four Wistar rats were randomly divided into seven groups of 12 rats in each: group 1 (sham laser therapy); group 2 received 3 J/cm(2) at one point; group 3 received 3 J/cm(2) at 24 points; group 4 received 72 J/cm(2) at 1 point; group 5 received 6 J/cm(2) at 1 point; group 6 received 6 J/cm(2) at 24 points; and group 7 received 144 J/cm(2) at 1 point. All experimental groups underwent LLLT immediately after TRAM surgery and on the next two following days, for three sessions in total. The percentage of the area of skin flap necrosis was calculated on the fourth postoperative day and two samples of skin were collected from each rat with a 1-cm(2) punch to perform mast cell evaluations with toluidine blue dye. RESULTS Statistically significant differences were found in the percentage of necrosis, and higher values were seen in group 1 than in all other groups. Among groups 3-7 no statistically significant differences were found (p < 0.292). For mast cells, when group 1 was compared to groups 5 (6 J/cm(2) at 1 point) and 7 (144 J/cm(2) at 1 point), it had fewer mast cells. CONCLUSION LLLT at a wavelength of 670 nm was effective at reducing the necrotic area, and we found that it can stimulate mast cells growth to increase vascular perfusion.