NITRIC OXIDE METABOLISM FEATURES UNDER CONDITIONS OF EXPERIMENTAL INFECTED RADIATION-INDUCED SKIN INJURIES DEVELOPMENT AND THEIR TREATMENT WITH PHOTODYNAMIC THERAPY

The aim: To follow-up nitric oxide content values in rat serum at the development of Staphylococcus aureus infected radiation skin injuries and their photodynamic therapy. Materials and methods: Eighty WAG male rats were studied in an experiment. Four groups were identified for evaluation. Group 1 included unaffected intact rats (n=20). Group 2 involved rats (n=20) with a modeled radiation-induced ulcer of the skin. The rats (n=20) with a modeled radiation-induced skin ulcer followed by infecting with Staphylococcus aureus were referred to group 3. Group 4 included rats (n=20) with Staphylococcus aureus infected radiation skin ulcer exposed to photodynamic therapy. Rats of groups 1-4 were sampled for biochemical blood examination on days 7, 14, 21, 30 and 45. Total nitric oxide metabolites (nitrites and nitrates) were measured according to V.A. Metelskaya et al. method. Results: Infectious agent (Staphylococcus aureus) present in skin ulcer impairs nitric oxide metabolism in rat blood serum that manifested in decreased total nitric oxide metabolites content on day 7, followed by its increase within days 14 to 45. While photodynamic therapy exposed on the Staphylococcus aureus infected radiation skin ulcer, total nitric oxide metabolites in blood serum had increased by day 7, but days 14 to 45 level was compliant with physiological norm. Conclusions: Infecting radiation skin ulcers with Staphylococcus aureus causes impaired nitric oxide metabolism, while photodynamic therapy helps to normalize the metabolism of the above-mentioned chemical compound that can improve healing of radiation skin ulcers.