Within the framework of scientific cooperation between National Pirogov Memorial Medical University and SI "Institute of Blood Pathology and Transfusion Medicine of the National Academy of Medical Sciences of Ukraine" (Lviv) the effect of 0.9 % NaCl solution (control drug) and HAES-LX-5 % infusion solution at a dose of 10 ml/kg into the inferior vena cava for 7 days on the skin structure of intact rats, as well as on early (1, 3 and 7 days) and late (14, 21 and 30 days) periods after burn damage of the skin of the II-III degree with an area of 21-23 % of the body surface was investigated.
Mature male rats, whose average weight was 160-180 g, were divided into 5 groups: group I – animals that underwent only femoral vein catheterization (intact rats, n=9); group II – catheterized animals without burns, with intravenous infusion of 0.9 % NaCl solution (n=54); group III – catheterized animals without burns, with intravenous infusion of HAES-LX-5 % (n=54); group IV – catheterized animals after skin burns, with intravenous infusion of 0.9 % NaCl solution (control) (n=54); group V – catheterized animals after skin burns, with intravenous infusion of HAES-LX-5 % (study drug) (n=54). All manipulations on rats were carried out according to the recommendations of the European Commission for biomedical research in the use of animals and the recommendations of the State Pharmacological Center of the Ministry of Health of Ukraine and the "Rules of preclinical safety assessment of pharmacological agents (GLP)" and rules of humane treatment of experimental animals (approved by the Bioethics Committee of National Pirogov Memorial Medical University).
Histological examination of the skin of male rats, which during the first 7 days was administered 0.9 % NaCl solution or the drug HAES-LX-5 % found that in all periods of observation microscopic organization of skin components in both early and late stages of the study when entering these infusion solutions are similar to those in intact rats.
At the ultrastructural level of study of rat skin components with the introduction of 0.9 % NaCl solution or HAES-LX-5 %, these solutions during all observation periods also do not change the submicroscopic organization of the epidermis, intercellular substance, cells and blood capillaries of the fibrous connective tissue of the papillary and papillary tissue.
It was found that at the light-level of the study in the early stages of the experiment (1, 3 and 7 days) after thermal injury under conditions of 0.9 % NaCl solution compensatory-adaptive changes in the structural components of the skin are combined with signs of destructive disorders. In the epidermis of the affected area of skin there is the destruction of epithelial cells (all its layers). Vascular disorders in the dermis are combined with changes in fibroblasts, homogenization and edema of the components of the intercellular substance.
In the late stages of the experiment (after 14, 21 and 30 days) there is a deepening of destructive changes in the structural components of the skin in the affected area. This process becomes irreversible. As a result, the formation of granulations and their maturation are slow. Marginal epithelialization of the wound with the formation of a full, differentiated into layers of regenerate is also slowed down. After 30 days of the experiment under the conditions of application of 0.9 % NaCl solution in the healing area there are no formed papillae of the dermis and skin appendages.
At the ultrastructural level of the study of the skin of male rats after thermal trauma under the conditions of previous application of the first 7 days of 0.9 % NaCl solution it was found that in the early stages of the experiment – stages of shock and early toxemia (1, 3 and 7 days) compensatory-adaptive changes combined with signs of destructive disorders. In the epitheliocytes of the epidermis of the affected area of skin there is the destruction of the nuclei and cytoplasm. Vascular disorders in the dermis are combined with changes in fibroblasts, the intercellular substance of fibrous connective tissue.
In the late stages of the experiment – the stages of late toxemia and septicotoxemia (14, 21 and 30 days) there is a further development and deepening of destructive-dystrophic changes of all ultrastructural components of the affected skin, which often become irreversible. The processes of granulation tissue formation, its transformation into connective tissue, as well as marginal epithelialization are slow.
