THE EFFECT OF ULTRAVIOLET RADIATION ON THE ORGANIZATION AND STRUCTURE OF COLLAGEN FIBERS OF DERMIS

The aim is to study the features of the influence of local ultraviolet radiation on the organization and structure of collagen fibers in the radiation area. The studies were performed on 30 albino guinea pigs weighing 400-500 g, exposed to local ultraviolet radiation. Animals were removed from the experiment after 2 hours, 4 hours, 3 days, 8 days after irradiation. The control group was intact guinea pigs. To assess the structure and location of collagen fibers, skin sections in the irradiated area were studied using histological methods with polarized light analysis of collagen, and they were also analyzed using a scoring system for three parameters: composition, refraction intensity, and orientation of collagen fibers. The revealed structural features of collagen fibers reflect the course of the process of degeneration of the collagen skeleton of the dermis with a violation of the orientation and ordering of collagen fibers and an increase in the content of type III collagen with an increase in the observation period. According to the results of a semi-quantitative assessment of the state of collagen fibers, a significant deterioration in their structure and composition was recorded starting from 4 hours after exposure to ultraviolet radiation and progressed with an increase in the observation period. On the 8th day, the maximum deviation from the structure of the normal dermis is determined by the total number of points. The influence of local ultraviolet radiation in the minimum erythema dose on the skin of guinea pigs leads to the development of disturbances of the organization (abnormal position and ordering) and structure (increase in collagen content of type III) of collagen fibers of the dermis, which progress with an increase of the observation period.