Role of gasotransmitters (nitric oxide (NO) and hydrogen sulfide (H2S)) in the functioning of digestive system is the subject of many modern researches. It was previously shown that NO and H2S display dose-dependant effects in gastric mucosa and colon. However the role of NO and H2S in mechanisms of cytoprotection and ulcerogenesis of in small intestine is still purely studied. That is why, the aim of our research was to study effects of H2S donors (NaHS та L-cysteine) on parameters of NO-system and the level of oxidative stress in small intestine of rats under condition of drug-induced enteropathy caused by the introduction of nonsteroidal anti-inflammatory drug – indometacine. Indometacine (30 mg/kg, subcutaneously) was used to induce enteritis, NaSH (1 and 10 mg/kg) and L-cysteine were introduced intraperitoneally twice after indometacine; 3 days after injection of drugs enteritis had developed. In the mucosa of small intestine were determined: alterations in malonic dialdehyde (MDA) concentrations activities of mieloperoxydase (MPO), superoxide dismutase (SOD), catalase (CAT), inducible and constitutive NO-synthases (iNOS and cNOS). Indometacine-induced enteritis was accompanied by: the rise of iNOS activity (4 fold, р ≤ 0.01) and the decrease of cNOS activity (more than twice, р ≤ 0.01) and arginase activity by 43 %, р ≤ 0.01. Introduction of all of studied H2S donors caused the decrease of iNOS activity and the increase of activities of both cNOS and arginase as compared to indometacine action. Indometacine-induced enteritis increased MPO activity (by 64 %, р ≤ 0,01) and MDA concentration and fall in SOD and CAT activities, resulting in formation of oxidative stress. H2S donors decreased MPO activity, still they were higher than in a control group. 1 mg/kg of NaHS practically returned MDA concentration to its control level, 10 mg/kg of NaHS and L-cysteine also decresed it. NaHS demonstrated dose-depandant effect on SOD and CAT activities. 1 mg/kg of NaHS substentially increased it, but its dose of 10 mg/kg practically din’t change tham. Thas, H2S donors NaHS and L-cysteine influenced on parameters of NO-syntase system in small intestine under condition of indomethacine-induced enteritis, that may be the evidence of relationship between H2S and NO-generating systems. H2S was involved in mechanisms cytoprotection in small intestine via reducing oxidative and nitrative stress manifestations and MPO activity.
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