CORRELATION OF ZONULA-OCCLUDENS ZO-1 ANTIGEN EXPRESSION AND TRANSENDOTHELIAL RESISTANCE IN PORCINE AND RAT CULTURED CEREBRAL ENDOTHELIAL-CELLS

Cerebral endothelial cell cultures (CECC) have been utilized as an in vitro system for simulating the blood-brain barrier. We have studied the expression of a tight junction associated protein (ZO-1) concomitantly with measurements of transendothelial electrical resistance and freeze-fracturing to test the barrier properties of CECC monolayers and, thereby, their capability in serving as an in vitro blood-brain barrier model. Freshly isolated CECC aggregates and 7 day old CECCs in primary culture express the ZO-1 protein. Measurements of the transcellular resistance of CECC monolayers yielded an electrical resistance of about 90-OMEGA-cm2. The low electrical resistance of cerebral endothelial monolayers together with the reduced complexity of the tight junction complement in vitro are indicative of reduced barrier properties of the in vitro system.