In the dissertation the actual scientific problem of pathophysiology was solved - on the basis of experimental data important mechanisms of damaging action of ultraviolet A and ultraviolet B on skin after irradiation, in the postheritemic period, the expediency of application of preparationswith antioxidant activity for reducing the identified violations is theoretically and experimentally substantiated. As a result of the conducted microscopic and morphometric researches new data are received that after local fractional irradiation by ultraviolet A in skin of guinea pigs the morphological picture in all structural components of skin has inhomogeneous character. It was found that local ultraviolet A irradiation leads to the development of negative processes in the blood (formation of peroxynitrite, abrupt activation of inducible nitric oxide synthase, accumulation of nitrites, nitrates, total metabolites of nitric oxide, decreasing of activation of antioxidant enzymes and development of uncompensated lipid peroxidation) and in focus (increased formation of nitrites, nitrates, total metabolites of nitric oxide, increase of the content of secondary products of lipid peroxidation, decrease of the activity of antioxidant enzymes) after irradiation. It was shown that under the influence of an ointment with antioxidant activity (ointment of thiotriazoline with silver nanoparticles) in the prophylactic mode the damaging effect of ultraviolet A is leveled. Alternative and hyperplastic processes in the epidermis are limited, alternative changes, signs of dermal collagenization are restored / rare; the activity of antioxidant enzymes increases in the hearth (to normal) and blood, reduces the formation of secondary products of lipid peroxidation, inhibits the formation of peroxynitrite, the expression of inducible nitric oxide synthase (to normal) and the production of nitric oxide derivatives (nitrites, nitrates, common metabolites in the blood and hearth). It is shown that local irradiation of guinea pig skin with ultraviolet B leads to pronounced violations of its morphofunctional state, which consists of the prolonged nature of the disorders, the chronicity of the inflammatory process. At the same time on the 8th-15th day after irradiation the predominance of proliferative phenomena of inflammation is observed. Increased proliferative activity of basal keratinocytes causes the development of hyperplastic processes in the epidermis, combined with dystrophic changes in epidermocytes and dyskeratosis. The collagenization of the dermis increases, the structure of elastic fibers changes. In parallel, the severity of leukocyte decreases and lymphomacrophage infiltration of the dermis increases. In the remote terms of the experiment (21-28th day) the severity of the proliferative activity of basal keratinocytes, hyperplastic and dystrophic changes of the epidermis, inflammatory infiltration of the dermis decreases, with increasingof uneven fibrosis. It was found that local ultraviolet B irradiation in the remote post-erythematous period leads to a multiple increase of peroxynitrite content and activity of inducible nitric oxide synthase, accumulation of nitric oxide products (nitrites, nitrates, total metabolites in the blood and focus), suppression of the activity of antioxidant enzymes and activation of lipid peroxidation processes in the blood and hearth throughout the study. It was found that the use of ointments with antioxidant activity (thiotriazoline ointment and thiotriazoline ointment with silver nanoparticles) in the treatment-and-prophylactic mode has a beneficial effect on the recovery process.
