SubpopulaÃÃes de linfÃcitos CD4, CD8 e CD45RB em enxertos esplÃnicos autÃlogos heterotÃpicos de camundongos sadios e esquistossomÃticos: estudo comparativo com o baÃo intacto e o remanescente esplÃnico vascularizado

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

Schistosomiasis mansoni is an infectious disease caused by a worm (Schistosoma mansoni), which has the human as one of the definitive hosts in its evolutive course. In more advanced stages, massive embolization by eggs layed in the portal venous sistems by adult forms of the parasite to the hepatic parenchima occurs; this leads to inflammatory reactions in the liver structure, modifying the architecture of the organ, with granuloma formation, whose resolution causes Symmers fibrosis, histhological characteristic of the chronic stage of the disease. This fibrosis causes resistance to the free passage of portal blood stream through the liver, with the consequent venous hypertension in the site of distal esophagus and gastric fundus, where varicae are formed, whose rupture can lead to episodes of upper digestive bleedings. Splenectomy is a meaningful part of surgical treatment for schistosomotic portal hypertension: per si, can reduce about 35 to 40% of blood pressure in portal vein territory. Despite its motivation, spleen removal may reduce immune responses of individuals to infectious challenges, mainly those caused by encapsulated germs. Studies have confirmed that spleen slices autoimplanted in animals and humans are able to regenerate. Although controversies still persist because central necrosis occurs whithin the implants with consequent mass reduction, it is believed that splenic implants restores spleen function as a lymphoid organ, and components of the immune system returns to previous serum levels. The purpose of this study was to experimentally verify if lymphocyte CD4, CD8 and CD45RB subsets are reestablished in autoimplanted splenic tissue. Adult female mice of GIDE non-isogenic strains were initially divided into 2 groups: A - control group (75 healthy animals) and B - study group (100 animals infected subcutaneously with 25 cercariae of Schistosoma mansoni); 120 days after the infection, animals of both groups were separated into 6 subgroups: A1 and B1 - intact spleens; A2 and B2 - partial splenectomy with preservation of vascularized spleen upper pole; and A3 e B3 - autoimplantation of sliced whole spleen into an omental pouch. Eight animals from each of the 6 subgroups were sacrificed between 60 and 65 days after operations, and the whole spleen, the vascular splenic remnant or autoimplants were collected. Mononuclear cells of splenic tissue were harvested and isolated for immunophenotyping; CD4, CD8 and CD45RB lymphocyte subsets were studied by flow cytometry. Liver biopsies of all animals were analised by optic microscopy, searching for the absence or the presence of hepatic fibrosis between healthy or infected mice, respectively. Spleen tissues specimens were obtained from 3 animals of each of the 6 subgroups for histological analysis. This experimental model offers sufficient material of schistosomotic splenic tissue to be studied in the chronic stage of disease; microscopic examination showed fibrosis in livers of all animals submitted to cercariae infection; all animals in the heathy control groups showed normal livers. Only splenic tissue obtained from infected mice showed schistosomotic granulomas, no matter the subgroup. Histological analysis showed no differences in the red and white pulps of whole spleen or its remnant, when compared both healthy animals and infected mice. Intersticial fibrosis was more evident in the morphology of autoimplants, when compared to whole spleens or vascular remnants; this microscopic pattern was identified in all autoimplants, from both the control and schistosomotic animals. Lymphocyte subsets were reestablished in splenic autoimplants either from healthy or infected anÃmals. The conclusion, therefore, is that there were no differences between all groups of animals in this study related to CD4, CD8 and CD45RB lymphocyte subsets measured in splenic tissue by flow cytometry

ASSUNTO(S)

schistosomiasis mansoni cirurgia linfÃcitos-subpopulaÃÃes-enxertos splenic implants esquitossomose mansÃnica-camundongos-auto-inplante esplÃnico citometria de fluxo-enxertos esplÃnicos-linfÃcitos autoimplant lymphocyte cirurgia experimental-baÃo-imunologia

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