Gut microbiota represents a relevant factor that may strongly interfere with the pathophysiology of parasitic infections, determine the parasite survival and the outcome of parasitic infections. Therefore probiotics can play an important role in reducing the pathogenicity of many parasites. Nematode Trichinella spiralis causes an intestinal and tissue disease – trichinellosis characterized by the enteritis (induced by adult worms) and the inflammation with degenerative changes in the skeletal muscles (induced by larvae). The chemotherapy of trichinellosis with anthelmintics is active only against adult worms, but not against muscle larvae. Therefore, the need for developing new methods for controlling this disease is living and anti-parasitic potential of probiotic bacteria could be successful. The immunomodulatory activity of probiotic bacteria is expressed through inhibition of inflammatory response, stimulation of phagocytic activity and activation of antigen presenting cells. Macrophages are antigen presenting cells – essential in the process of phagocytosis, they release cytokines and regulate inflammation. After contact with the antigen, they stimulate and produce reactive oxygen species that are highly toxic to parasites. Superoxide anion O2- is the basic component of macrophage activity. This study was focused on the effect of probiotic and bacteriocin-producing bacterial strains on the production of superoxide anion in peritoneal macrophages of Trichinella spiralis infected mice.
The strains (Enterococcus faecium EF55, Enterococcus faecium 2019 = CCM7420, Enterococcus faecium AL41 = CCM8558, Enterococcus durans ED26E/7, Lactobacillus fermentum AD1 = CCM7421, Lactobacillus plantarum 17L/1) were administered to mice daily at the dose of 100μl (109 CFU/ml) and mice were infected with 400 T. spiralis larvae on the 7th day of probiotic therapy. Production of the superoxide anion in the peritoneal macrophages was detected ex vivo. The E. faecium EF55 and E. faecium CCM8558 strains increased the O2- production prior to parasitic infection, on the day 7 of application. The administration of lactobacilli and enterococci to mice significantly stimulated the metabolic activity of macrophages throughout the experiment, with the exception of the day 18 after infection (p.i.), when a significant inhibition of the superoxide anion formation occurred in the mice with application of E. durans ED26E/7. The most significant immunomodulatory effect on the peritoneal macrophage metabolic activity during the intestinal phase of T. spiralis infection showed the strains E. faecium CCM7420 and E. faecium CCM8558, and during the muscular phase of infection the strains L. fermentum CCM7421 and L. plantarum 17L / were also positively useful.
The increase in the metabolic activity of peritoneal macrophages induced by probiotic therapy in the intestinal phase of trichinellosis supported the host anti-parasite deffence and resulted in the decreased infectivity of larvae caused by damage and killing of newborn larvae with reactive oxygen species from macrophages. Therapeutic approaches with probiotics could help to reduce the risks of infestation by parasites or complement classical anti-parasite treatments.
The study was supported by the VEGA 2/0056/19 and APVV-17-0028.