Evaluation of the effect of the combined effects of local anti-inflammatory therapy (Ivermectin) and a pulsed dye laser (595 nm) on LL-37 induced rosacea-like inflammation on mice

Introduction. Rosacea is a chronic inflammatory dermatosis characterized by the presence of pathogenesis of inflammation and vascular changes caused by exposure to antimicrobial peptides (LL-37) and toll-like receptors (TLR2). It has been established that the pathogenetic link is a target for a new therapy of rosacea. Objective – to evaluate the potential combined effect of local Ivermectin 1 % cream and a pulsed dye laser (PDL) with a wavelength of 595 nm on a model of rosacea-like inflammation on mice after 4-fold introduction of recombinant antimicrobial peptide LL-37. Material and methods. Adult female BALB/c white mice weighing 23.5±0.66 g were used, divided into 4 groups: control; group 2 (biodistillate water was introduced in a volume of 40 μl, within 48 hours); group 3 (without treatment, intracutaneously injected paravertebrally into the lumbar region 40 μl of peptide LL-37 (320 μM), 4 times every 12 hours); group 4 (with treatment, 1 % Ivermectin cream was applied after each peptide injection, 60 hours after the first injection, the PDL device with a wavelength of 595 nm was treated, the area irradiated with a surface of 50 mm2). Results. The result indicates that the local injection of LL-37 into the skin of mice caused a dramatic expansion and fullness of the vessels of both the arterial and venous link. The integrity of the walls of the blood vessels of the microcirculatory bed in the dermis and the hypodermis has broken, resulting in multiple small hemorrhages in the tissues. In the remaining vessels, the endothelium was swollen, the adventitia was infiltrated with leukocytes. The number of mast cells increased significantly, but only some of them degranulated. Conlusions. As a result of the combined local anti-inflammatory and laser effects, leukocyte infiltration of the dermis and hypodermis decreased, in the dermis a part of the vessels was desolate, the endothelium in them was swollen. Enlarged full blood vessels remained in the hypodermis, the endothelium was absent in them, insignificant adventitia infiltration remained. The proposed combination of effects, taking into account the morphological picture, is promising and requires additional study in patients with rosacea without the use of invasive research methods.