Perfil leucocit?rio sist?mico e les?es no trato gastrointestinal de camundongos infectados experimentalmente pelo Trypanosoma cruzi por via oral.

Programa de P?s-Gradua??o em Ci?ncias Biol?gicas. N?cleo de Pesquisas em Ci?ncias Biol?gicas, Pr?-Reitoria de Pesquisa de P?s Gradua??o, Universidade Federal de Ouro Preto.A Doen?a de Chagas, causada pelo protozo?rio Trypanosoma cruzi, ? end?mica em quase todos os pa?ses da Am?rica Latina. No Brasil, a transmiss?o por via vetorial e transfusional foi controlada pela vigil?ncia epidemiol?gica, tornando a infec??o pela via oral o principal mecanismo de transmiss?o da doen?a no pa?s. O trato gastrointestinal ? a porta de entrada para o parasito por essa via de infec??o, no entanto, pouco se sabe sobre o envolvimento desses ?rg?os e do perfil parasitol?gico e imunopatol?gico frente ? via oral. Diante nisso, o objetivo deste trabalho foi avaliar o perfil leococit?rio sist?mico e as altera??es histopatol?gicas no trato gastrointestinal de camundongos infectados pela via oral com a cepa Berenice-78 do T. cruzi nas fases aguda e cr?nica. Para isso, 140 camundongos Swiss foram distribu?dos em tr?s grupos experimentais: controle n?o infectado; infectados por via intraperitoneal (VIP); infectados por via oral (VO). Esses animais foram inoculados com 1x105 formas tripomastigotas metac?clicas provenientes de culturas acelulares por gavagem (VO) ou por via intraperitoneal (VIP). Quatro animais de cada grupo foram eutan?sia dos nos dias 14, 21, 28, 35, 42 e 180 ap?s a infec??o (DAI), sendo coletados fragmentos do est?mago, duodeno e c?lon. Foram ent?o analisados ou quantificados a curva de parasitemia e a taxa de sobrevida; a fenotipagem de c?lulas mononucleares (mon?citos, linf?citos T CD4+ , T CD8+ e B) do sangue perif?rico por citometria de fluxo; o parasitismo tecidual por meio da t?cnica de PCR em tempo real; o processo inflamat?rio, empregando a colora??o de Hematoxilina & Eosina e a neoforma??o de col?geno, empregando a colora??o de Tricr?mico de Masson. O grupo VIP apresentou pico de parasitemia no 24? DAI (530.754 tripomastigotas/0,1 ml de sangue), e o grupo VO mostrou pico de parasitemia um pouco maior, tamb?m no 24? DAI (628.085 tripomastigotas/0,1 ml de sangue). A taxa de sobrevida dos animais infectados por via oral foi de 47,63%, j? o grupo VIP apresentou uma sobrevida de 87,75%. Quanto ? resposta imune, observou-se uma redu??o no percentual de mon?citos j? no 14? DAI no grupo VO enquanto que no VIP n?o houve altera??es em seus percentuais. Com rela??o aos linf?citos, foi observada uma redu??o mais precoce dos linf?citos T CD4+ e dos linf?citos B do sangue perif?rico dos animais do grupo VO em compara??o com o grupo VIP. J? os linf?citos T CD8+ aumentaram a partir do 21? DAI tanto no grupo VIP quanto no VO. O parasitismo tecidual mostrou-se aumentado no grupo VO no 28? DAI no est?mago, duodeno e col?n quando comparado a grupo VIP. Em rela??o ao infiltrado inflamat?rio, no est?mago foi observado um aumento no 28?DAI em ambos os grupos infectados. J? no duodeno esse aumento s? ocorreu no grupo VO, e no c?lon, n?o se observa diferen?as significativas entre o n?mero de c?lulas inflamat?rias ao longo da infec??o nos animais do grupo VO. N?o foram observadas diferen?as significativas quanto ? neoforma??o de col?geno. Diante disso, estes dados sugerem que a infec??o oral possui um distinto perfil de resposta parasitol?gica e imunopatol?gica em compara??o com a via intraperitoneal, sendo que a via oral apresentou um maior parasitismo tecidual nos ?rg?os do trato gastrointestinal avaliados durante a fase aguda.Chagas disease, caused by protozoan Trypanosoma cruzi, is endemic in almost all countries of Latin America. In Brazil, vector and transfusion transmission was controlled by epidemiological surveillance, becoming oral infection the most important mechanism of transmission of the disease in several regions of the country. The gastrointestinal tract is the gateway to parasite by this route of infection, however, little is known about the involvement of these organs and the parasitological and immunopathological profile related to oral route. Based on this, the objective of this work was to evaluate systemic profile leukocyte and the histopathological changes in the gastrointestinal tract of infected mice with the T. cruzi Berenice-78 strain in acute and chronic phases. For this, 140 Swiss mice were distributed in three experimental groups: uninfected control; infected by intraperitoneal route (IR); infected by oral route (OR). These animals received an inoculum of 1x105 metacyclic trypomastigote forms from acellular cultures by gavage (OR) or intraperitoneally (IR). Four animals from each group were necropsied on days 14, 21, 28, 35, 42 and 180 after infection (DAI), and fragments of the stomach, duodenum and colon were collected. The parasitemia curve and the survival rate were then analyzed or quantified; The phenotyping of mononuclear cells (monocytes, CD4+ T, CD8+ T and B lymphocytes) of the peripheral blood by flow cytometry; Tissue parasitism using the realtime PCR technique; The inflammatory process, using the Hematoxylin & Eosin staining and the collagen neoformation, using the Masson's Tricromic staining. IR group showed a peak of parasitemia in 24th DAI (530,754 trypomastigotes/0.1 mL of blood), and OR group showed a slightly higher parasitemia, also in 24th DAI (628,085 trypomastigotes/0.1 ml of blood). The survival rate among the orally infected animals was 47.63% and IR group had survival rate of 87.75%. Regarding the immune response, there was a reduction in the percentage of monocytes already in 14th DAI in OR group whereas in IR there were no changes in their percentages. With regard to lymphocytes, an earlier reduction of CD4+ T lymphocytes and B lymphocytes in peripheral blood was observed in OR group compared to IR group. Whereas CD8+ T lymphocytes increased in 21th DAI in both IR and VO groups. The tissue parasitism was increased in OR group in 28th DAI in stomach, duodenum and colon when compared to IR group. In relation to inflammatory infiltrate, an increase in 28th DAI in both infected groups was observed in stomach. In duodenum, this increase only occurred in OR group, and in colon, there were no significant differences between the number of inflammatory cells throughout the infection in animals of OR group. There were no significant differences in collagen neoformation. Therefore, these data suggest that oral infection has a different profile of parasitological and immune response compared to intraperitoneal route, being the oral route more virulent and with greater tissue parasitism in organs of the gastrointestinal tract evaluated during the acute phase