 This study investigates the therapeutic paracrine action of bone marrow mesenchymal stem cells, MSCs, on interleukin-9, Illinois-9, levels in an adjuvant-induced arthritis, AIA, RAP model and evaluates the enhancement effect of Hesperidin, HSD, on transplanted MSCs. The results suggest that MSCs decreased Illinois-9 levels in AIA and combined therapy with HSD can alleviate oxidative stress and enhance stem cells' immunomodulatory action. This article was authored by Sahasopi Abdul-Hailam, Nawal Zakaria Haggag and Nazwar Ahmed El-Shinawi.