Evaluation of the possible therapeutic role of omega-3 on ankle joint and lung in a model of rheumatoid arthritis in rats: A histological and immunohistochemical study

Abstract

Introduction: Rheumatoid arthritis (RA) is a chronic inflammatory systemic autoimmune disease. Lung disease has been recognized as a common complication of RA. Omega-3 is an essential fatty acid with wide range of activity. Aim of the work: To investigate the possible therapeutic role of omega-3 free fatty acid on the structure of ankle joint and lung in a model of adjuvant-induced RA in rats. Materials and Methods: Thirty adult male albino rats were divided into three groups; Group I served as a control group. Group II was used as a model of RA. Rats of this group were given single subcutaneous injection of 0.1ml of complete Freund adjuvant in their hind paws. Group III (omega 3-treated group), omega-3 was given in as a dose of 300 mg/kg orally administered after two weeks of RA induction and continued daily for another two weeks. The ankle joint and the lungs from all groups were dissected out after two and four weeks and processed for light microscopic examination. Histomorphometric studies and statistical analysis were also done. Results: RA was confirmed histologically in the ankle joint after two weeks and was aggravated after four weeks. Erosion of articular cartilage and mononuclear cellular infiltration in the synovium were noticed in both time points. Moreover, the lungs after two weeks showed focal inflammatory cellular infiltration and pulmonary fibrosis that were more evident after four weeks of untreated RA. This was associated with significant increase in the mean area percentage of collagen fibers and number of cells positive for TNF-α immunohistochemical reaction compared to the control group. Omega-3 treated group illustrated improvement of both ankle and lung structures. Conclusion: Omega-3 significantly ameliorated the structural damage of ankle joint and lung after RA induction.

Effect of Formaldehyde on The Structure of The Lung and Heart and The Possible Protective Effect of Omega- 3 (Histological and immune-histochemical study)

“…These results were confirmed by the previous studies which showed that elevating tissue omega-3 levels can prevent and treat fine particle-induced health problems and suppress fine particle-induced pulmonary and systemic inflammation (Li et al, 2017). The therapeutic role of omega-3 was confirmed also by (Raafat et al, 2018) who found that the addition of omega-3 has an ameliorating effect on the inflammation caused due to rheumatoid arthritis on the lung tissue by H&E and (TNF-α). The anti-inflammatory effect of omega-3 was studied also by (xu et al,2011) who said that omega-3 injection effectively reduces destruction and injury in the lung of rats with severe scald.…”