الفهرس 
Literature ReviewOnly 14 pages are availabe for public view
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Abstract
Rheumatoid arthritis is an incurable autoimmune and chronic inflammatory disorder, manifested in chronic inflammation of joints which causes the destruction of cartilage and synovial joints.
However, various medications are used to treat rheumatoid arthritis, but they are given to reduce inflammation and stop case worsening. It was also found that these medications are not effective in approximately 30% of patients and have adverse side effects with increasing infections susceptibility. Surprisingly, taking advantage of cell therapy promise has raised high hopes for treating RA. Myeloid-derived suppressor cells (MDSCs) represent a population of heterogeneous myeloid lineage cells that have the potent immunosuppressive activity of T cell activation and function. It was demonstrated that MDSCs are involved in several autoimmune disorders, including rheumatoid arthritis. Two perspectives exist regarding the role of MDSCs in RA (anti-inflammatory or pro-inflammatory role). Mesenchymal stem cells (MSC) are adult multipotent progenitor cells that are able to differentiate into a various cell types and tissues and have the potentials of immunomodulatory functions. BM-MSCs have been shown to induce human MDSC expansion and function in vitro and via paracrine effects through hepatocyte growth factor. However, understanding the implication of MDSCs and MSCs in arthritis may favor their potential use in immunotherapeutic strategies. The present study aimed to examine the functional role of myeloid-derived suppressor cells in the pathogenesis of adjuvant induced arthritis, explore the relationship between stem cells and myeloid-derived suppressor cells and examine the possible role of mesenchymal stem cells in developing a line for treatment of hepatic, cardiac and splenic histological lesions as a sequel of rheumatoid arthritis.
In the present study, 60 young adult male albino rats were used. Rats were randomly allotted into three groups of 20 each as follows: - group one (C): was kept as control and injected with normal saline 0.9%. group two (AIA): injected with complete Freund’s adjuvant for arthritis induction. group three (AIA+MSCs): injected with complete Freund’s adjuvant for arthritis induction then by day 10 they received intra-articular injection with MSCs.
Current results revealed a significant increase in the mean values of MDSCs percentage in AIA group compared to control group accompanied by elevated level of WBCs, ANA, IL-1β, IL-4, IL-6, IL-10, TNF-α, M-CSF, iNOS and Arg-1. On the other hand, MSCs treatment produced a significant decrease in cytokine levels compared to AIA rats promoting the suppressive effect of MSCs.
Histologically, AIA group showed severe arthritis characterized by destruction of the articular cartilage and synovial membrane inflammation. Hepatic lesions in AIA rat sections were encountered as diffused vacuolations and inflammatory cell infiltrations. The cardiac tissue manifested myocarditis, congested blood vessels and degenerative necrotic myocytes. Most of these alterations returned to near to normal profiles following 4-week MSCs therapy.
In conclusion, it was suggested that MDSCs might exhibit different functions in autoimmune diseases. The applicable therapeutic strategies aimed at transplantation or elimination of MDSCs under different physiological and pathological conditions should be considered. Also, knowing the implication of MDSCs and MSCs in arthritis may prefer their potential use in immunotherapeutic strategies. Nevertheless, the number of investigations about the interplay between MSCs and MDSCs is limited, and new studies are necessary to improve a full general picture about the molecular and biological interaction between these non-transformed cells. At present, only distinct information of MDSCs and MSCs roles can be obtained. Therefore, it is necessary to accomplish new studies addressing the mutual collaboration of MSCs and MDSCs which can provide new platforms for developing better and personalized therapies for immune diseases treatment and thus improve patients’ quality of life.