Carrera Silva E.1; Arocena A.2; Pellegrini A.3; Cano  .4; Paroli A.5; Aoki M.6; Gea S.7 CIBICI - CONICET. FCQ - Universidad Nacional de Córdoba1

Toll-like receptor (TLR) and cytokine signalling play a central role in pathogen clearance and in pathological phenomena. Recently, we reported a fatal hepatic injury associated with low TLR2, TLR4 and high TLR9 expression and an exacerbated inflammatory response in C57BL/6 (B6) mice during Trypanosoma cruzi acute infection. In this work, we evaluated whether treatment with TLR ligands - previous or during T. cruzi infection - improves or exacerbates the observed inflammato y r sponse. We used 10ug of Pam3CSK4, 10ug of LPS or 5ug of CpGODN per dosis, a day previous to infection (-1) or 7 and 14 days post infection (+7/+14 dpi). In each group, we comparatively studied parasitemia, survival percentage, GOT and GPT transaminase activities, cytokine production and histopathology. The treatment with any of the three agonists during acute infection (+7/+14), increased the GPT activity but the pre treatment (-1) reduced the GOT and GPT activities compared to untreated infected mice. The parasitemia diminished only in Pam3CSK4 (-1) mice, but the survival did not differ in any group compared to untreated infected mice. Purified hepatic leucocytes from infected mice previously treated with any of the three ligands showed a significant reduction of IL6, IL12 and TNFa levels at 14dpi compared to infected mice alone. In addition, nitric oxide secretion was significantly reduced at 14 and 21dpi.Histop thological studies revealed a reduction of liver inflammatory cell foci independently of any ligand treatment. Our results suggest that the pre-treatment with Pam3CSK4, LPS or CpG one day before infection, reduces the inflammatory environment in hepatic tissue and could be a promissory strategy to modulate the exacerbated inflammatory process in B6 T. cruzi infected mice.

Toll-like receptor (TLR) and cytokine signalling play a central role in pathogen clearance and in pathological phenomena. Recently, we reported a fatal hepatic injury associated with low TLR2, TLR4 and high TLR9 expression and an exacerbated inflammatory response in C57BL/6 (B6) mice during Trypanosoma cruzi acute infection. In this work, we evaluated whether treatment with TLR ligands - previous or during T. cruzi infection - improves or exacerbates the observed inflammato y r sponse. We used 10ug of Pam3CSK4, 10ug of LPS or 5ug of CpGODN per dosis, a day previous to infection (-1) or 7 and 14 days post infection (+7/+14 dpi). In each group, we comparatively studied parasitemia, survival percentage, GOT and GPT transaminase activities, cytokine production and histopathology. The treatment with any of the three agonists during acute infection (+7/+14), increased the GPT activity but the pre treatment (-1) reduced the GOT and GPT activities compared to untreated infected mice. The parasitemia diminished only in Pam3CSK4 (-1) mice, but the survival did not differ in any group compared to untreated infected mice. Purified hepatic leucocytes from infected mice previously treated with any of the three ligands showed a significant reduction of IL6, IL12 and TNFa levels at 14dpi compared to infected mice alone. In addition, nitric oxide secretion was significantly reduced at 14 and 21dpi.Histop thological studies revealed a reduction of liver inflammatory cell foci independently of any ligand treatment. Our results suggest that the pre-treatment with Pam3CSK4, LPS or CpG one day before infection, reduces the inflammatory environment in hepatic tissue and could be a promissory strategy to modulate the exacerbated inflammatory process in B6 T. cruzi infected mice.