Local cryotherapy improves adjuvant-induced arthritis through down-regulation of IL-6 / IL-17 pathway but independently of TNFα

International audienc

Skin temperature after cold application.

<p>Skin temperature was measured on hind paws (on both ankles and tarsae) just after each cold application using a temperature probe. The mean temperature (<b>A</b>) as well as the minimal temperature (<b>B</b>) on the 4 joints were calculated for each treated AIA rat. Results are expressed as means ± SEM (n = 9–10 rats). 2-way ANOVAs with Bonferroni post-tests were used. NS: non significant.</p

Cytokine plasmatic levels in non-arthritic, non-treated arthritic and cryotherapy-treated arthritic rats.

<p>Plasma levels of IL-6 (<b>A, E, I</b>), IL-17A (<b>B, F, J</b>), IL-1β (<b>C, G, K</b>), TNF-α (<b>D, H, L</b>) were assessed in AIA rats treated or not either by being placed into cages lined with ice pops for 30 minutes (n = 10) or by intermittent cold gas spray applications on hind paws for 2 minutes (n = 9), twice a day for 14 consecutive days from day 11 to day 24 post-immunization. Results are expressed as means ± SEM (n = 7–10 rats/group). Mann-Whitney tests were used. ***p<0.001, **p<0.1, *p<0.05.</p

Correlations between pro-inflammatory cytokine levels and clinical parameters.

<p>Pearson’s r correlation coefficients were calculated between hind paw IL-6 (<b>A, D</b>), IL-17A (<b>B, E</b>), IL-β1 (<b>C, F</b>) gene expression levels and clinical parameters, and between plasma levels of IL-6 (<b>I</b>), IL-17A (<b>G, H</b>), TNF (<b>J</b>) and clinical parameters measured at day 24 post-immunization in AIA treated or not either by being placed into cages lined with ice pops for 30 minutes (n = 10) or by intermittent cold gas spray applications on hind paws for 2 minutes (n = 9), twice a day for 14 consecutive days from day 11 to day 24 post-immunization. For the arthritis score and ankle diameter, AIA rats from the 3 treatment groups and non-arthritic controls were considered (n = 60, n = 64, n = 60 pairs for hind paw IL-6, IL-17A and IL-1β mRNA levels and n = 35 pairs for both IL-17A and TNF-α plasma levels respectively). For ankle diameter, both hind paws from the 3 treatment groups were considered (n = 50, n = 56, n = 50 pairs for hind paw IL-6, IL-17A and IL-1β mRNA levels and n = 28 pairs for both IL-17A and IL-6 plasma levels respectively).</p