Effects Of 1,25-dihydroxy Vitamin D₃ On The Expression Of RANKL Protein Of Rheumatoid Arthritis Fibroblast-like Synoviocytes Of IL-22 Mediated

Background:Rheumatoid arthritis(RA) is a kind of autoimmune disease which is mainly characterized by residual arthritis. The destruction of bone and cartilage is the key link of RA deformity, and osteoclasts play a key role in the destruction of bone. The activation of nuclear factor kappa B ligand(RANKL) increase is a necessary condition for osteoclast differentiation. 1,25-(OH)2D3 can significantly reduce the level of Thl7 cytokine IL-17, IL-22, IL-6 and TNF-α in patients with RA. IL-22 is thought to the main factors that contribute to the Th17 cell pathology function-- inflammatory response and tissue destruction. Our previous study found that, in patients with RA serum RANKL level was significantly higher than that of the control group. IL-22 induce RA fibroblast-like synoviocytes RANKL expression by activating JAK-2/STAT-3 and p38 MAPK signaling pathway. This effect can be suppressed by 1,25-(OH) 2D3 at the mRNA level. However, have 1,25-(OH)2D3 has the same inhibitory effect on the expression of RANKL protein? We need further study.Objective:Verify whether 1,25-(OH)2D3 can block the activation of JAK-2/STAT-3 and p38 MAPK signaling pathway, which activated by IL-22, thereby inhibiting RANKL protein expression in fibroblast-like synoviocytes of RA patients. To delay the progression of bone destruction in RA. To provide a theoretical basis for early diagnosis and treatment of clinical RA.Methods:1. Culture the fibroblast-like synoviocytes of RA patients in vitor;2. Use rhIL-22, JAK-2/STAT-3 pathway inhibitors(AG490), p38 MAPK pathway inhibitors( SB203580) and 1,25-(OH)2D3 to treat 4-7 generation of fibroblast-like synoviocytes and divided into control group, IL-22 group, IL-22+1,25-(OH)2D3 group,IL-22+ JAK-2/STAT-3 pathway inhibitors group, IL-22+ p38 MAPK pathway inhibitors group, IL-22+ JAK-2/STAT-3 pathway inhibitors +1,25-(OH)2D3 group, IL-22+ p38 MAPK pathway inhibitors +1,25-(OH)2D3 group. Extract the total protein of the cells.Detect the expression of RANKL protein using Western Blot method;3. Statistical analysis using SPSS17.0 statistical software.Results:1. Cultured the fibroblast-like synoviocytes of RA patients in vitor for 5 generation successfully.2. Compared with the control group, the relative expression of RANKL protein was significantly increased in the IL-22 group(P<0.05);3. Compared with the IL-22 group, the relative expression of RANKL protein was significantly decreased in the IL-22+JAK-2/STAT-3 pathway inhibitor group and the IL-22+p38 MAPK pathway inhibitor group(P<0.05);4. Compared with the IL-22 group, the relative expression of RANKL protein was significantly decreased in the IL-22+1,25-(OH)2D3 group(P<0.05);5. Compared with the IL-22+1,25-(OH)2D3 group, the relative expression of RANKL protein was significantly increased in the IL-22+1,25-(OH)2D3+JAK-2/STAT-3pathway inhibitor group(P<0.05);6. Compared with the IL-22+1,25-(OH)2D3 group, the relative expression of RANKL protein was significantly increased in the IL-22+1,25-(OH)2D3+ p38 MAPK pathway inhibitor group(P<0.05).Conclusion:1,25-(OH)2D3 can block the activation of JAK-2/STAT-3 and p38 MAPK signaling pathway, which activated by IL-22, thereby inhibiting RANKL protein expression in fibroblast-like synoviocytes of RA patients, which delay the process of bone destruction of RA indirectly.