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.

BACKGROUND DATA

Low-level laser therapy (LLLT) has been reported to be capable of changing mast cell numbers and degranulation in experimental burns in rats.

OBJECTIVE

We conducted a study of the influence of LLLT on mast cells in a rat model of third-degree burn.

METHODS

In this study we divided 48 rats equally into two groups of 24 rats each. Third-degree burns were inflicted at three different locations on each rat in each group. The first burn site on rats in group I was treated with 890-nm pulsed laser, 75W peak, 80 Hz, 180 ns, average power 1mW, illuminated area 1 cm(2), 1 mW/cm(2), 856 sec, 0.924 J/cm(2). The second burn site on both groups of rats was treated with 0.2% nitrofurazone cream. Mast cell numbers and degranulation at each burn site on each group of rats were then assessed at 4, 8, 13, and 20 days after the infliction of burns.

RESULTS

Analysis of variance on day 4 showed that the total numbers of mast cells were significantly lower at the laser-treated burn sites than at other burn sites on both groups of rats. On day 8 the total numbers of mast cells were again significantly lower at the laser-treated burn sites than at other burn sites, and on day 13, the numbers of both types 1 and 2 mast cells were significantly lower at the laser-treated burn sites than at other burn sites.

CONCLUSIONS

We conclude that LLLT can significantly decrease total numbers of mast cells during the proliferation and remodeling phases of healing in a rat model of third-degree burn.