Effects of low-level laser therapy on mast cell number and degranulation

Abstract

Abstract-Mast cells have been shown to participate in the wound healing process. We investigated the effects of low-level laser therapy (LLLT) on mast cell number in the inflammation, proliferation, and remodeling phases of the wound healing process of experimental burns. Sixty rats subjected to third-degree burns were divided into four groups: two laser-treated, one control, and one nitrofurazone-treated group. In the two lasertreated groups, burned areas received LLLT with a helium-neon laser at energy densities of 38.2 J/cm 2 and 76.4 J/cm 2 , respectively. The effects on mast cell number and degranulation were assessed 7, 16, and 30 days postburn (inflammation, proliferation, and remodeling phases of wound healing, respectively). Intact and degranulated mast cells were counted. Five rats with no burns were used for baseline studies. On day 7 in the first laser group, the total number of mast cells was significantly higher than in the other groups. On day 16 in the nitrofurazonetreated group, the total number of mast cells was significantly higher than in the control, first laser, and normal groups. LLLT on the experimental third-degree burns significantly increased the total number of mast cells during the inflammation phase of wound healing; also, topical application of 0.2% nitrofurazone ointment on the same burns significantly increased the total number of mast cells during the proliferation phase of burn healing.

InGaP 670-nm laser therapy combined with a hydroalcoholic extract of Solidago chilensis Meyen in burn injuries

“…The density energy used in this experimental model has been used by our research group with favourable results for tissue repair [15,51,52], and the literature reports that different authors used similar energy density [13,24,25,53]. Non-contact laser irradiation was performed punctually, in the continuous mode, at a distance of ±2 mm and an angle of 90°in relation to the wound surface.…”

Effect of Low-Level Treatment with an 80-Hz Pulsed Infrared Diode Laser on Mast-Cell Numbers and Degranulation in a Rat Model of Third-Degree Burn

“…In the first and second laser-treated groups the burns were subjected daily to low-level helium-neon laser irradiation with energy densities of 38.2 and 76.4 J/cm 2 , respectively. Bayat et al 22 observed at 7 days after injury in the first laser-treated group that the total numbers of mast cells were significantly higher than in the other groups.…”

“…[10][11][12][13][14][15][16][17][18][19][20] We had previously studied the effects of LLLT on mast cells during the burn healing process. 21,22 In our first study, 21 we inflicted deep second-degree burns on rats. In the first and second laser-treated groups the burns were subjected daily to low-level helium-neon laser irradiation with energy densities of 1.2 and 2.4 J/cm 2 , respectively.…”

“…We reported 21 at 7 and 16 days after injury that the number of type 1 mast cells in the first laser-treated burns was significantly higher than in control burns. In our second study, 22 we inflicted third-degree burns on rats. In the first and second laser-treated groups the burns were subjected daily to low-level helium-neon laser irradiation with energy densities of 38.2 and 76.4 J/cm 2 , respectively.…”

Anti-inflammatory effects of low-level laser in burn wound models in rats

“…Bayat et al [33] examined the effects of low-level helium-neon laser on rats that had received third-degree burns and reported a significant increase in total quantity of mast cells and newly created epidermal cells at the burn lesion site in the group treated with laser therapy compared with the control group. Chiarotto et al [16] evaluated the effects of InGaP (670-nm) and GaAlAs (830-nm) on second-degree burns in rats and reported similar results of decrease in granulocyte numbers, increase in angiogenesis and fibroblast proliferation, which were reported to expedite the healing process of the second-degree burns after laser therapy.…”