Morphological and immunohistochemical changes in oxazolone-induced ulcerative colitis under ozone therapy

Abstract

Introduction. Inflammatory bowel diseases are a serious medical and social problem due to the increase in morbidity and disability among the young, able—bodied population. The aim of the study was to investigate the effect of intraperitoneal and rectal ozone therapy on the morphology and morphometry parameters of the damage zone in oxazole-induced ulcerative colitis in the dynamics of the experiment. Materials and Methods. The study was performed on 97 male Wistar rats. Experimental colitis (EC) was modeled using oxazolone (Sigma-Aldrich; USA). The first stage included skin sensitization by applying 150 ml of a 3% alcohol solution of oxazolone to the interscapular area of the animal, the second stage was a rectal injection of 150 ml of a 3% alcohol solution of oxazolone per rectum to a depth of 7–8 cm. Zoletil-100 (INN: tiletamine hydrochloride) (VirbacSanteAnimale; France) was used for anesthesia at a dose of 20 mg/kg. Morphometry was performed using ImageScope M program (Russia). Colon tissue damage was assessed using tissue damage index (TDI). The content of neutrophils (NF), lymphocytes (LC), eosinophils (EO), histiocytes (HC), plasma cells (PC), fibroblasts (FB) per 1 mm2 was determined in the focus of colorectal damage. Ulcerous defect diameter (in μm) on a PrimoStar microscope (CarlZeiss, Germany), with a Pro150ES morphometric unit (Pixera Corporation, USA). Results. At EC on the second, fourth and sixth days DAI increases, in the lesion of the colon an ulcerous defect is fixed, TDI, the content of NF, LC, EF, PC, HC, FB increase. The intraperitoneal application of ozone was shown to have a positive effect on the tissue morphometry indices of the lesion focus; on the second day and in dynamics on the fourth and sixth day the significant limitation of the ulcerous defect area with the parallel gradual decrease of the tissue damage index (TDI) in comparison with the similar indices in group II was registered. In the rectal variant of ozone application the dynamics of changes in the inflammatory infiltrate composition was also characterized by the significant increase of all parameters on the second, fourth (except for EF), sixth (except for NF, EF) day in comparison with the group of intact animals. The size of the ulcerous defect and tissue damage index after rectal application of ozone on the second day was significantly smaller than in the group with EC and in the intraperitoneal ozone application group, but did not reach the values of the intact group, i.e. there was no complete recovery. Discussion. In experiments on rats it was demonstrated that intraperitoneal injection of ozone at a dose of 150 mg/kg reduces streptozotocin-induced pancreatic damage by increasing the amount of glutathione transferase in the gland tissue, activation of Nrf2-dependent transcriptional pathways, increase in serum insulin and leptin levels. Under clinical conditions the hepatoprotective effect of O3 was shown, as well as an increase in the effectiveness of traditional hepatoprotectors when the latter are combined with O3. Conclusions. Application of ozone therapy in oxazolone-induced ulcerative colitis revealed a positive effect of ozone on the morphological picture of the lesion area and the dynamics of changes in the cellular composition of the inflammatory infiltrate. A more pronounced positive effect of local application of ozone in the form of rectal ozone therapy on morphometry parameters was recorded: normalization on the sixth day of the neutrophil count, more pronounced reduction of the ulcerous defect area, reduction of the tissue damage index.