Placental Trypanosoma cruzi infection is restricted by nitric oxide production by endothetial nitric oxide synthase isoform

Abstract

Human placenta avoids Trypanosoma cruzi (T. cruzi) infection by differentmechanisms and the production of nitric oxide (NO) is one of them.Objective: To elucidate the importance of NO production in the parasiticload in placental tissue and the relevance of endothelial nitric oxide synthase(eNOS) isoform as a major NO producer.Methods: Placentas from caesarean delivery from clinically andserologically healthy women and Trypomastigotes of T. cruzi isolatedfrom a congenital case (named Lucky) were used. Placental villi explantswere co-cultured in RMPI 1640 for 24 h with or without(control) 1 x106 trypomastigotes of Lucky (TcII -VI strains). Cultureswere treated with NOS inhibitor NG-nitro-L-arginine methyl ester (LNAME)at 0.1 and 1 mM. Quantification of eNOS expression byimmunohistochemistry and Western blot, nitrite level in media supernatantwith Griess technique, and parasitic load by qPCR withTaqman probes were assayed.Results: Placental explants in the presence of T. cruzi showed a significantincrement of eNOS protein abundance (7.2 ± 0.94 fold, P<0.05) mainly at thesyncytiotrophoblast, b