Intestinal inflammation and synovitis during non-lethal Salmonella enterocolitis in mice.

NOTO LLANA, MARIANGELES; GIACOMODONATO, MONICA ; SARNACKI, ; GARTNER ALEJANDRA S; CERQUETTI, M. CRISTINA.

Sapporo

Congreso; IUMS 2011 Congress. XIII International Congress of Bacteriology and Applied Microbiology.; 2011

IUMS

We investigated inflammatory responses of intestine and knee joints in a mouse model for non-lethal enterocolitis.  BALB/c mice were inoculated orally with 20 mg of streptomycin and 24 hs later they received 103 CFU of a virulent strain of Salmonella Enteritidis by the same route. At different time post-infection animals were sacrificed and samples were obtained.  Salmonella was recovered from PeyerLs patches up to day 4 and from spleen up to day 14.  Bacteria were neither recovered from knee joints nor from draining lymphnodes. In line with gut histological changes, infected mice showed a significant increase (p < 0.05) in intestinal IL-17 and TNF-ƒ¿, determined by qPCR. Twenty-one days post-infection animals presented synovitis in the knee joints, suggesting that this non-lethal model of Salmonella enterocolitis is suitable for studying reactive arthritis.  We then tested the effect of probiotics in preventing the joint sequelae. Thus, mice were fed with commercially-available Lactobacillus casei, ad libitum, for 7 days before Salmonella infection.  We found that PeyerLs patches and spleen of mice pretreated with probiotics were less colonized with Salmonella, and for a shorter period.  In addition, probiotic feeding previous to Salmonella infection resulted in a significant decrease (p < 0.05) of gut inflammatory cytokines, compared to infected animals not receiving Lactobacillus.  TNF-ƒ¿ levels decreased from 7.5 + 0.8 a.u. in infected mice to 1.4 + 0.5 a.u. in pretreated animals.  More dramatic, IL-17 intestinal levels diminished from 24 + 4 a.u. in infected mice to 2.4 + 0.9 a.u. in pretreated animals. Consequently, Salmonella-induced synovitis was prevented in mice pretreated with probiotics.  Altogether, our results showed that the non-lethal model for enterocolitis might be useful not only for studying the pathogenesis of Salmonella-induced synovitis but for therapeutic and preventive approach.