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.

Levofloxacin induces differential effects in the transcriptome between the gut, peripheral and axial joints in the Spondyloarthritis DBA/1 mice: Improvement of intestinal dysbiosis and the overall inflammatory process

To analyze the effect of levofloxacin-induced intestinal microbiota modifications on intestinal, joint, and systemic inflammation in the DBA/1 mice with spontaneous arthritis. The study included two groups of mice, one of which received levofloxacin. The composition and structure of the microbiota were determined in the mice's stool using 16S rRNA sequencing; the differential taxa and metabolic pathway between mice treated with levofloxacin and control mice were also defied. The effect of levofloxacin was evaluated in the intestines, hind paws, and spines of mice through DNA microarray transcriptome and histopathological analyses; systemic inflammation was measured by flow cytometry. Levofloxacin decreased the pro-inflammatory bacteria, including Prevotellaceae, Odoribacter, and Blautia, and increased the anti-inflammatory Muribaculaceae in mice's stool. Histological analysis confirmed the intestinal inflammation in control mice, while in levofloxacin-treated mice, inflammation was reduced; in the hind paws and spines, levofloxacin also decreased the inflammation. Microarray showed the downregulation of genes and signaling pathways relevant in spondyloarthritis, including several cytokines and chemokines. Levofloxacin-treated mice showed differential transcriptomic profiles between peripheral and axial joints and intestines. Levofloxacin decreased the expression of TNF-α, IL-23a, and JAK3 in the three tissues, but IL-17 behaved differently in the intestine and the joints. Serum TNF-α was also reduced in levofloxacin-treated mice. Our results suggest that the microbiota modification aimed at reducing pro-inflammatory and increasing anti-inflammatory bacteria could potentially be a coadjuvant in treating inflammatory arthropathies.

Treatment with silica-gold nanostructures decreases inflammation-related gene expression in collagen-induced arthritis

Gold salts have been used to treat rheumatoid arthritis (RA) since the 1940s, and, with advances in nanotechnology, the use of nanogold provides multiple options for anti-inflammatory therapies. This paper presents the synthesis and characterization of silica-gold nanostructures (SGNs) and their therapeutic effect in collagen-induced arthritis (CIA) in DBA/1 mice. At the end of the treatment, the synovial membranes, kidneys, livers, and spleens were dissected and analyzed by inductively coupled plasma mass spectroscopy (ICP) showing less than 0.0001 and 0.1% of the administered doses of Au and Si, respectively. Remains of the SGNs were visually identified in the synovial membrane by scanning electron microscopy (SEM), and the bone density of the hind paws was observed by computerized tomography (CT) indicating a reduction of porosity in the CIA-experimental group. The DNA microarray analysis carried out with RNA obtained from the hind paws showed 2628 differentially expressed genes (DEGs) by SGNs. The bioinformatic analysis showed that DEGs were significantly associated with several inflammatory signalling pathways including chemokines, cytokine-cytokine receptor interaction, PI3K-Akt, TNF, IL-17, NFκβ, MAPK, and RA. SGNs downregulated relevant inflammatory genes in the arthritic joints, including Tnf, Ifng, Il6, and Cxcl5; immunohistochemistry (IHC) confirmed the reduction of TNFα, IL-6, NFκβ, and VEGF in the joints due to the effect of SGNs. TNFα and IL-6 were also reduced in the serum of DBA/1 mice treated with SGNs.

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.