EFFECTS OF DEHYDROEPIANDROSTERONE AND MELATONIN ON TRYPOMASTIGOTE FORMS OF THE Y STRAIN TRYPANOSOMA CRUZI, AND IN VIVO NITRIC OX

AC12

Kuehn, C. C. , Oliveira, L. G. R. , DOS Santos, C., Caetano, L. C. , Coutinho, J. V.,Ferreira, D. S., Esperandim, V. R., Prado Junior, J. C.

Laboratório de Parasitologia, Departamento de Análises Clínicas, Bromatológicas e Toxicológica, Faculdade de Ciências Farmacêutica de Ribeirão Preto – USP,

EFFECTS of Dehydroepiandrosterone and MELATONIN ON TRyPOMASTIGOTE FORMS OF the Y STRAIN TRYPANOSOMA CRUZI, and in vivo nitric oxide production in J774 macrophages. biomédico_chris@hotmail.com Christian Collins Kuehn(1), Luiz Gustavo Rodrigues Oliveira(2), Carla Dos Santos(2), Leony C. Caetano(2), Jacqueline Viana Coutinho(2) Viviane Rodrigues Esperandim(2), Daniele da Silva Ferreira(2) José Clóvis do Prado Junior (3). 1- autor, 2- co-autor, 3- orientador/pesquisador. Laboratório de Parasitologia, Departamento de Análises Clínicas, Bromatológicas e Toxicológica, Faculdade de Ciências Farmacêutica de Ribeirão Preto – USP, Introduction In this year of 2008 - closer to the 100th anniversary celebration of the discovery of Chagas´ disease, the non-existence of an efficient drug against blood and tissue protozoaries still remain one of the first leading causes of morbidity and mortality by this disease in more than 18 million infected people. All the drugs prescribed nowadays cause several side effects which lead us to the searching of a new drug capable to potencialize and modulate the immune system  for host control of parasitic level, and decreased side effects. Objectives: To evaluate the in vivo actions of Dehydroepiandrosterone  (DHEA) and Melatonin (MEL) hormones in trypomastigote form of  T.cruzi Y strain, and the quantification of nitric oxide in J774 macrophages infected by T.cruzi Y strain. Methods:  trypomastigote form of  Y strain (2.5_X10⁶) were placed in contact  with different hormones concentrations 0.5, 8.0, 20, 32, 40, and 128μM being evaluated by colorimetric procedures where the color intensity was propoportional to the number of viable parasites, and the results expressed according to the inhibitory concentration of 50%  of parasite growth (IC50). The J774 macrophages were plated with 5 x 106/well, and infected with trypomastigote forms (2.5 x 106)/well by direct contact with the concentrations 0.5, 8.0, 20, 32, 40, and128μM.  After 24h the NO was measured by quantifying. Concentration was determined by a wave length of 570nm with a microplaque reader. The issues were accomplished in triplicate. Results: Parasitic lises after treatment with DHEA/MEL demonstrated IC50 of 41.42. Nitric oxide production  expressed   in mM in J774 infected macrophages treated with DHEA/MEL during 24h showed a decrease when compared to the control infected with P<0.05. Conclusion: A  tripanomicidal action by the hormones on tripomastigote forms   of Y strain by macrophages simultaneously infected and treated with hormones was observed.  The necessary concentrations used for rich a tripanocidal action, and an inhibiton of oxidant effects on this infected cells are high in relation  to the physiologic concentrations secreted by pineal and adrenal glands.  The endogenous productions of DHEA and MEL may be in enough concentrations in the iNO  induction process. However our study using concomitant  DHEA/MEL may offer a new antioxidant mechanism for individuals carrying acute cases of Chagas´ disease.