Fig. 4

Effects of 5-hydroxytryptophan (5-HTP) on the expression of pro-inflammatory mediators in the arthritic joints. a mRNA levels (mean ± standard error) of TNFα, IL-6, IFNγ, IL-22, cyclooxygenase-2 (COX-2) and NF-κB (p65) in the arthritic joints. b Immunohistochemistry staining for TNFα, IL-6 and COX-2 in the arthritic ankles. The expressions of these proteins in the areas with mononuclear cell infiltration (positive area) were measured using a digital camera and Image-Pro Plus 6.0 software (Media Cybernetics Inc., Bethesda, MD, USA). The grouping was as described in Fig. 3a. At least four mice in each group were studied. *Significant compared with group 1. Multiple comparisons were performed using the Kruskal–Wallis test, if significant (p <0.05), then the Duncan test was used to find out which pairs were different