<i>Trypanosoma cruzi</i> infection induces <i>Cox2</i>, <i>Tbxas1</i>, <i>Edn1</i> and <i>Nppa</i> in infected heart tissue.

<p>(A and B) C57BL/6 (<i>black circles</i>) and BALB/c (<i>white circles</i>) mice were infected with 2×10³ blood-trypomastigote forms of the Y strain. (A) Parasitemia expressed as the mean ± standard error of the mean (s.e.m.) of the number of parasites per 5 µl of blood. (B) Percent of mice survival. Results are representative of 2 independent experiments, each performed with 6 mice per group. (C) Tissue inflammation, parasitism and COX-2 expression in heart from uninfected (left panels) and <i>T. cruzi</i>-infected (21 days post-infection, right panels) mice. Representative results of histological analysis (Mason's trichrome staining) of cardiac tissue specimens from BALB/c and C57BL/6 mice (top and center panels, respectively) are shown. Bars = 100 µm. Bottom panels display representative results of COX-2 immunostaining (IS) in the hearts from C57BL/6 mice. Original magnification for microphotographs ×400. (D) <i>Cox2</i> (COX-2), <i>Tbxas1</i> (TXS), <i>Edn1</i> (ET-1) and <i>Nppa</i> (ANP) gene expression in the heart during the acute phase of infection in C57BL/6 and BALB/c mice. RNA from heart tissue at different days post-infection was used to perform RT-PCR with specific probes, and normalized to ribosomal 18S RNA as described in ‘<a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0002034#s2" target="_blank">Materials and Methods</a>’. Values are expressed as means ± s.e.m. from 3 independent infections, each performed with 3 mice per group. *<i>P</i><0.05. (E) Levels of circulating peptides (ET-1 and ANP) and eicosanoids (PGF_2α and TxB₂) in the sera of uninfected (<i>black bars</i>) and <i>T. cruzi</i>-infected (<i>grey bars</i>) C57BL/6 mice. Mouse sera were collected before and after 21 days of infection, and were assayed in triplicate by capture ELISA for ANP (top panel), ET-1 (central panel), PGF_2α and TxB₂ (bottom panel). Each bar represents the mean values for groups of 6 mice ± s.e.m. Similar results were obtained in two additional experiments. ^*<i>P</i><0.05; ^**<i>P</i><0.01.