Fig. 2

TRPA1 mRNA expression is increased following stimulation with inflammatory factors IL-1β, IL-17, LPS, and resistin in primary human OA chondrocytes (a-d) and in human T/C28a2 chondrocyte cell line (e). Isolated primary human OA chondrocytes were stimulated with IL-1β (1–100 pg/ml) (a), IL-17 (10–100 ng/ml) (b), LPS (10 ng/ml) (c). and resistin (0.3–3 μg/ml) (d); and human T/C28a2 chondrocytes with IL-1β (1–100 pg/ml), IL-17 (100 ng/ml) and LPS (10 ng/ml) (e) for 24 h; and thereafter total RNA was extracted. TRPA1 mRNA levels were measured by qRT-PCR, and the results were normalized against GAPDH mRNA levels. The results are expressed as a percentage in comparison to untreated control samples, which was set as 100 %. Primary chondrocyte samples were obtained from four different donors and the experiments were performed in duplicate. Human T/C28a2 chondrocyte experiments were carried out in quadruplicate. Results are expressed as mean + SEM. Repeated measures ANOVA (a, b, d) and one-way ANOVA (e) followed by Dunnett’s post-test or paired t test (c) was used in the statistical analysis; ^* p < 0.05 and ^** p < 0.01, compared to the untreated control samples. IL interleukin, LPS lipopolysaccharide, OA osteoarthritis, TRPA1 transient receptor potential ankyrin 1