Resumen

LUGO DE YARBUH, Ana et al. Efecto de la infección aguda con Trypanosoma cruzi sobre el sistema nervioso central de rata gestante. RFM [online]. 2009, vol.32, n.1, pp.16-24. ISSN 0798-0469.

This study analyzed the effect of acute infection with Trypanosoma cruzi on the histology of Central Nervous System (CNS) of rats during pregnancy. Wistar rats were infected by intraperitonealy inoculation of 5x10⁴ blood trypomastigotes of the M/HOM/Bra/53/Y strain. To obtain pregnancies during the ascending phase of parasitemia, rats in estrus of its menstrual cycle were matched with males at days 12 after infection (pi). Virgin/infected, virgin/healthy and healthy/pregnant rats were used as controls. High levels of patent parasitemia (PP) of 36 ± 2.9 to 55 ± 3.0 tripanosomas/mm³ blood, were observed in rats between 16 and 22 infection days and between 6 and 12 pregnancy days respectively. The comparison of the PP between infected/ pregnant rats and virgin/infected rats was significant at 1 %. At the 30 days pi rats were sacrificed. Brain (B) and regions cervical (CR), thoracic (TR), lumbar (LR) and sacra (SR) of Spinal cord (SC) samples were obtained and fixed in formalin to 10 %, dehydrated and embedded in Paraplast. The sections (7 μm) stained with Hematoxylin and Eosin showed inflammatory reaction of polymorphonuclear and mononuclear cells and plasmocytes in contact with neurons of B of the infected/pregnant rats. The comparison between lymphocytes number in the right (HR) (65 ± 6.3) and left (HL) (48 ± 4.5) cerebral hemispheres of infected/pregnant rats and of 20 ± 2.0 and 13 ± 1.1 lymphocytes in healthy/pregnant rats was significant (P<0.05). The comparison between lymphocyte number in the HR y HL of the virgin/healthy rats and virgin/infected rats not showed differences. Motoneurons (MN) reduction of 35 ± 3.4 to 16 ± 1.7 in CR, of 33 ± 3.1 to 21 ± 3.0 in TR and of 31± 3.8 to 10 ± 1.8 in LR of the SC of infected/pregnant rats was significant (P<0.05), when they were compared with MN number in SC of healthy/pregnant rats. Reduction of MN of 53 ± 4.9 to 35 ± 3.4 in the CR and of 37 ± 3.3 to 22 ± 1.9 in the SR of the SC was observed, when they were compared with MN number between virgin/healthy and healthy/pregnant rats. The immunocytochemical assay of sections of B using Glial Fibrilar Acid Protein, Indirect immunofluorescence-Propidium Iodide and Peroxidase-anti-Peroxidase, showed infection with presence of amastigotes and T. cruzi antigen in the cerebral hemispheres of infected/pregnant rats. Therefore it might be conclude that the increase of the PP and the cerebral trypanosomiasis in rats could be related to the changes in the immune response of the infected rats during gestation, favoring brain penetration of parasites. It might be probable that the presence of the parasite in the B of these rats, took place by the transmigration of infected inflammatory leukocytes cross the blood-brain barrier. The development of focal lymphocytes infiltrates in the cerebral and medular tissues and loss of MN in the SC of the infected/pregnant rats might induce neuropathological disorders in the pregnant mother.

Palabras clave : Rat; Pregnant; Trypanosoma cruzi; Acute Chagas´disease; Brain; Spinal cord; Motoneurons.