Rheumatoid arthritis mediator CD18 expression by Staphylococcus aureus superantigen C in rats

Background and Objectives: Microbial superantigens have been reported in the blood and synovial fluid of rheumatoid arthritis patients, raising the question of whether the presence of these superantigens could provoke the induction of inflam- matory biomarkers expression or not. The purpose of this study was to examine the Staphylococcus aureus superantigen C on CD18 expression. Materials and Methods: The superantigen C was purified by ultrafiltration. Immunoblotting was performed using a specific antibody. Also, 50 micrograms of superantigens (toxin) were injected intraperitoneally and intra-articularly into separate rat groups. Blood was collected and RNA extracted. Then, the cDNA was synthesized. The expression of CD18 marker was evaluated using RT-real-time PCR, and the results were descriptively analyzed. Results: The results of this study revealed that 50 μg of toxin, injected intra-articularly and intraperitoneally, showed the surplus expression of the marker CD18 in the blood of rats after 20 days. By this method, the expression of the marker CD18 was significantly different between rats that received the superantigen intra-articularly and intraperitoneally (2.10; 2.3 and 3.3 folds) and the controls (P≤ 0.05). Conclusion: The results indicated that the presence of Staphylococcal of superantigen C in the body of rats has enhanced the expression of the CD18 inflammatory marker more than 3 times. This valuable finding is an introduction to further research and could provide new methods to prevent and control inflammatory diseases, including rheumatoid arthritis.