Immunomodulatory effects of berberine on Staphylococcus aureus-induced septic arthritis through down-regulation of Th17 and Treg signaling pathways

Abstract

Objectives: The preseaant study was aimed to investigate the immunomodulatory effects of berberine on Staphylococcus aureus-induced septic arthritis through the downstream signaling mechanism of Th17 and Treg, in the control and prevention of disease progression of Staphylococcus aureus induced septic arthritis of blood, spleen and synovial joints. Methods: The study was conducted in mice induced with septic arthritis by S. aureus for 15 days. The infected mice were treated with berberine (50 or 100 or 200 mg/Kg) to evaluate the effects on the isolated cells of Th17 and Treg from synovial joints, blood and spleen against the septic arthritic induced mice followed by JNK, RANKL and NF-κB expressions in the lysates of Th17 and Tregs isolated cells. The evaluation of serum IL-21 and TGF-β levels was also conducted after 15 days post-infection in Th17 and Treg population. Results: Our findings showed that berberine exerted excellent inhibitory effects on the S. aureus (AS-789) strain for inducing sepsis-induced arthritis. The results from the S. aureus testing revealed that at concentrations below 640 μg/mL, the strain was more resistant to berberine, as it had an increased rate of growth. The assessment of S. aureus induced septic arthritis (joint swelling and arthritis index) substantial reduction in the joint swelling and arthritis index (p<0.01) in the berberine-treated groups. The percentage of Th17 cells with CD4 and RORγt; Treg cells with CD4, CD25 and FOXp3 in the synovial joints, blood and spleen was substantially declined in the drug-treated groups (p<0.01) as compared to the S. aureus infected mice. The TGF-β and IL-21 serum levels determinations in S. aureus induced septic arthritis revealed a substantial decrease in serum TGF-β levels (p<0.01) in drug-treated groups compared to the infected animals. The post hoc test revealed a substantial decrease in JNK, NF-κB and RANKL expressions in the lysates of Th17 and Treg isolated cells in the drug-treated animals (p<0.01) when compared to the S. aureus-infected cluster. Conclusion: Our findings demonstrated that a possible strategy for combating disease severity with berberine treatment in Staphylococcus aureus induced septic arthritis in mice, which targets the Th17 and Treg cells have driven the NF-κB/JNK-RANKL axis.