Avaliação da expressão de receptores da imunidade inata em linhagens de camundongos suscetíveis e resistentes a infecção pelo Schistosoma mansoni

Abstract

This study aimed to evaluate innate immune receptors expression in susceptible and resistant mouse strains to infection with Schistosoma mansoni. About 30 S. mansoni cercariae, LE strain, were inoculated subcutaneously into Balb/c, C57BL/6 and Swiss male mice. Two, seven, 12 and 16 weeks after infection (WAI) mice were euthanized and when possible evaluated the following parameters: parasitism by hepatic portal system perfusion, oogram, presence of hepatic granulomas, and cytokines of innate immunity (IL-1β, IL-6, IL-10, IL-12p35, IL-18 and TNF-α) mRNA expression, innate immunity Toll-like receptor (TLR1, TLR2, TLR3, TLR4, TLR5, TLR6, TLR7, TLR8, TLR9) mRNA expression, Nod-like receptor (NALP1 and NALP3), and adapter molecules (Myd88, ASC, and Caspase-1) mRNA expression in liver tissue, by Real-time PCR. Balb/c and C57BL/6 mice showed survival of 70%, while Swiss mice showed 100% survival when evaluated by 16 WAI. In two WAI Swiss mice showed higher NLRP1, NLRP3, caspase-1, IL-1β and IL-18 mRNA expression when compared to Balb/c and C57BL/6. Balb/c and C57BL/6 mice showed higher TLR2, TLR3, TLR5, NLRP3 and ASC mRNA expression in seven WAI when compared to the Swiss. In addition, Balb/c mice showed increased TLR6, TLR7, TLR9, MyD88, NLRP1 and TNF-α mRNA expression. Moreover, Swiss mice have a lower number of adult parasites in the hepatic portal system and fewer eggs in the distal ileum fragment in seven and 12 WAI when compared to Balb/c and C57BL/6. In conclusion, C57BL/6 and Balb/c mice showed high TLRs and NLRs receptors mRNA expression in seven WAI (oviposition beginning), suggesting intensify susceptibility to infection, with consequent increase in the mortality rate in these animals. Furthermore, Swiss mice exhibited increase initial inflammatory profile (in two WAI), which could assist in the control of parasitism. And the mRNA activation suppression of cytokines and receptors of innate immunity, in seven WAI, could cause lower mortality and greater resistance to infection during this period.