SUB-LETHAL DOSE OF SHIGA TOXIN2 (STX2) FROM ENTEROHEMORRHAGIC ESCHERICHIA COLI AFFECTS BALANCE AND CEREBELLAR ULTRASTRUCTURE

LUCIANA DALESSIO; ALÍPIO PINTO; CANGELOSI ADRIANA; GEOGHEGAN PATRICIA; TIRONI-FARINATI CARLA; BRENER GABRIELA; GOLDSTEIN JORGE

Boston, Massachusetts

Simposio; 9th Triennial International Symposium on Shiga Toxin (Verocytotoxin)-producing Escherichia coli (VTEC) meeting; 2015

Introduction: Stx2 may damage the CNS independently or concomitantly with HemolyticUremic Syndrome (HUS). Cerebellar dysfunction may occur following intoxication with Stx2, however studies regardingthis issue is scarce. The aim of this studywas to determine the cerebellar compromise after intravenous administration ofa sub-lethal dose of Stx2.Methods: Male NIH mice (25g) wereinjected intravenously with vehicle (control group), 0.5ηg, or 1ηg of Stx2 per mouse (sub-lethal dose). Cerebellar blood brain barrier permeability wasdetermined by the Evans blue assay while cell ultrastructure was determined by transmissionelectron microscope (TEM). Cerebellar functionality was studied by measuringthe fall angle in the inclined plane test during 23 days. Results and Discussion: Sub-lethal Stx2 significantly increased the blood brain barrier permeability(100 ± 15 folds, P<0.05 by Student´s t test). Lower scores of fall angle obtainedfrom the inclined plane test denoted a significant poor cerebellarfunctionality peaking at day 5 (48º ± 0.4 (Stx2) vs 54º ± 1.5 sub-lethal Stx2 vscontrol, P<0.05 by ANOVA-Bonferroni post hoc test). TEM analysis showed neurodegeneration in cells fromthe granulose cell layer and in Purkinje cells in a dose-dependent manner (73%± 4 1ηg Stx2, 50% ± 1.5 0.5ηg Stx2, 4% ± 2 control, P<0.05 by ANOVA-Bonferronipost hoc test). The presented data provide evidence that sub-lethal intravenous Stx2 altered the blood brainbarrier permeability in the cerebellum. This event allowed the toxin topenetrate the cerebellar parenchyma that led to the observed cell damage withfunctional implications in test balance. Implications: This experimental model may explain the cerebellar syndrome reported inpatients with HUS and it may provide the basis for future research in thissubject.