Effects of pulsed infra-red low level-laser irradiation on mast cells number and degranulation in open skin wound healing of healthy and streptozotocin-induced diabetic rats

Introduction: Low-level laser therapy (LLLT) has been reported to be capable of changing mast cell numbers and degranulation in experimental wounds. Objective: We conducted a study on the influence of pulsed LLLT on mast cells in wounds of non-diabetic and diabetic rats. Methods: Thirty-six rats were randomly divided into non-diabetic and diabetic groups. Type 1 diabetes milletes (DM) was induced in rats of the diabetic group by administration of streptozotocin (STZ). We inflicted two wounds in each rat. The first wound in both non-diabetic and diabetic groups was treated with an 890-nm laser, having pulse frequency of 80 Hz and energy density of 0.2 J/cm(2). Mast cell numbers and degranulation of all sub-groups were assessed at 4, 7, and 15 days after the infliction of the wounds. Results and conclusion: According to the paired t-test, the total number of laser-treated mast cells was significantly higher than that of the placebos in the non-diabetic groups on days 4 and 15. The total number of laser-treated mast cells was significantly higher than that of the placebos in the diabetic groups on days 4 and 15. The number of granulated mast cells was significantly higher than that of degranulated mast cells for all laser-treated mast cells and placebo mast cells of the non-diabetic and diabetic groups.