The gut microbiome (GM) of rheumatic arthritis (RA) patients is often altered in composition and function. Moreover, methotrexate (MTX), one of the most frequently used disease-modifying antirheumatic drugs, is known to negatively affect GM composition. The modulation of immune system activity is one of the therapeutic benefits of probiotics. The aim of the current investigation was to determine the impact of MTX therapy combined with one of the Lactobacillus strains, Lactoplantibacillus plantarum LS/07 (LB), on adjuvant arthritis (AA) in rats. Methods focused on biometric and inflammatory parameters in AA, particularly on plasmatic levels of IL-17A, MMP-9, and MCP-1, and the activities of gamma-glutamyl transferase in the spleen and joints were applied. Enhancing the effect of MTX, LB positively influenced all biometric and inflammatory parameters. The findings of the present study may be of help in proposing novel therapeutic strategies for RA patients.

Four in vitro oxidative‐stress models were used to study the antioxidant/antipollution effects of all‐trans‐astaxanthin and crocin compared to synthetic antioxidants. DPPH‐scavenging activity of astaxanthin (5 μM) was 2.4, 1.3, 1.4, 1.1 and 0.9‐fold higher than that of alpha‐tocopherol (AT), butylhydroxytoluene, butylhydroxyanisole, gallic acid and Trolox, respectively. Crocin scavenged the same radicals amount as butylhydroxytoluene and butylhydroxyanisole. Both carotenoids were more effective at reducing ferric ions than synthetic antioxidants and had a protective effect on the viability of stressed epidermal cells. Reactive oxygen species induced by hydrogen peroxide or cigarette smoke on a skin were quenched with astaxanthin and crocin to approximately the same extent as with AT. ASX was 3.8, 2.3 and 14‐fold better singlet oxygen scavenger than Trolox, AT and gallic acid, respectively. The polyunsaturated fatty acids in the astaxanthin’ emulsion were 6.5 and 2.5‐fold more resistant to oxidation than in the control emulsion and the AT’ emulsion, respectively.