Low-Intensity Physical Exercise Decreases Inflammation and Joint Damage in the Preclinical Phase of a Rheumatoid Arthritis Murine Model.

Lifestyle modifications in preclinical Rheumatoid Arthritis (RA) could delay the ongoing pathogenic immune processes and potentially prevent its onset. Physical exercise (PE) benefits RA patients; however, its impact in reducing the risk of developing RA has scarcely been studied. The objective was to describe the effects of low-intensity PE applied at the disease's preclinical phase on the joints of DBA/1 mice with collagen-induced arthritis (CIA). Twelve mice with CIA were randomly distributed into two groups: the CIA-Ex group, which undertook treadmill PE, and the CIA-NoEx, which was not exercised. The effects of PE were evaluated through clinical, histological, transcriptomics, and immunodetection analyses in the mice's hind paws. The CIA-Ex group showed lower joint inflammation and damage and a decreased expression of RA-related genes (Tnf Il2, Il10, Il12a, IL23a, and Tgfb1) and signaling pathways (Cytokines, Chemokines, JAK-STAT, MAPK, NF-kappa B, TNF, and TGF-beta). TNF-α expression was decreased by PE in the inflamed joints. Low-intensity PE in pre-arthritic CIA reduced the severity through joint down-expression of proinflammatory genes and proteins. Knowledge on the underlying mechanisms of PE in preclinical arthritis and its impact on reducing the risk of developing RA is still needed.

Stability of housekeeping genes in inflamed joints of spontaneous and collagen-induced arthritis in DBA/1 mice.

BACKGROUND: DBA/1 mice arthritis models have contributed to our understanding of human rheumatoid arthritis (RA) and spondyloarthritis (SpA) pathogenesis, as well as the exploration of therapeutic targets for treatment. Quantitative polymerase chain reaction (qPCR) is an indispensable tool in molecular research, which requires reference gene validation to obtain consistent and reliable results. OBJECTIVE: To determine the stability of candidate reference genes for qPCR in the joint of collagen-induced arthritis (CIA) and spontaneous arthritis (SpAD) DBA/1 mice. METHODS: The expression of eleven commonly used reference genes (ACTB, B2M, EF1a, GAPDH, HMBS, HPRT, PPIB, RPL13A, SDHA, TBP, and YWHAZ) was assessed by qPCR and the data were compared using delta-Ct methods and the geNorm, NormFinder, and RefFinder software packages. Genes identified as stable in each model were used for the quantification of inflammatory cytokines RESULTS: The gene stabilities differed between the two arthritis models in the DBA/1 mice. EF1a and RPL13A were the best reference genes for SpAD, while RPL13A and TBP were the best for the CIA. These genes allowed the data normalization for the quantification of the inflammatory cytokines in both models; these results showed an increase in the expression of IL-1B, IL-12B, IL-17A, and IL-6 in the inflamed joints. The use of different primer sequences for the same reference gene resulted in different relative quantification values. CONCLUSION: This study demonstrates that commonly used reference genes may not be suitable for arthritic tissues from DBA/1 mice, and strengthening the principle that meticulous validation of reference genes is essential before each experiment to obtain valid and reproducible qPCR data for analysis or interpretation.