Lesões de isquemia arteriovenosa e reperfusão em jejuno de equinos: imunoistoquímica de proteínas de junção e histopatologia

AUTOR(ES)

Aline Machado Rapello do Nascimento

DATA DE PUBLICAÇÃO

2007

RESUMO

To evaluate whether complete arteriovenous ischemia followed by reperfusion of mesenteric blood flow aggravates lesions involving small intestine of horses, β--catenin and occludin expressions were measured in jejune epithelia of seven equines, without definite breed. The animals had been submitted to aseptic ventral midline celiotomy and five jejune segments collected corresponding to a baseline segment, a five minutes segment subjected to ischemia, and three segments collected after being subjected to five, sixty and one hundred and twenty minutes of tecidual reperfusion, respectively. Experimentally induced lesions created by total arteriovenous occlusion followed by reperfusion were similar to naturally acquired lesions, as much in the period of ischemia as in the aggravation of the injuries observed during reperfusion. Changes that occur when ischemic intestine is reperfused are progressive, and include mucosal, submucosal, and serosal edema; polymorphonuclear and mononuclear cell infiltrates; and alterations in vascular patterns. Imunohistochemistry analyses have shown strong staining baseline segments for β-catenin in all animals and its progressive lack of staining during ischemia and reperfusion treatments. That indicates progressive lack of intercellular adherence. Similar results of specific decreases of total expression of Occludin, a tight junction protein, were observed. This protein is involved in regulating the movement of solutes in the paracellular pathway and also plays an important role in the maintenance of cell polarity. The reduction of expressions of both intercellular proteins measured directly demonstrates β-catenin injury due to progression of edema during ischemia and its aggravation during reperfusion and also shows an increase of the permeability of paracelular pathways and its related consequences to degradation of Ocludina.

ASSUNTO(S)

ciencias biologicas adherents junction junção de oclusão beta-catenin junção de aderência beta-catenina junction of occlusion ocludina occludin

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