Quantification of early blood-brain barrier disruption by in situ brain perfusion technique

Osmotic disruption is currently being used to circumvent the blood-brain harrier (BBB) and enhance the delivery of therapeutic molecules in human brains. To date, however, the time course during the early phase of disruption has not been clarified. In order to demonstrate the rapid change in cerebrovascular permeability after BBB disruption in rats. We developed a method of in situ brain perfusion to demonstrate the earliest reversibility in cerebrovascular permeability. Osmotic BBB disruption was attained by intracarotid infusion of hypertonic mannitol. Perfusate containing [C-14]-sucrose was infused at different little points following osmotic stress followed hy measuring cerebrovascular pertneability. The earliest BBB disruption as seen to occur 5 min after osmotic stress, after which the exact time course of cerebrovascular reversibility was studied. The protocol reported here. in contrast with those reported in previous was shogun to be qualitative, simple and fast. In addition, the method call be applied to measure any low BBB permeability molecules. This protocol should be helpful for any research focused on enhancing drug delivery into the brain following osmotic BBB disruption. (C) 2001 Elsevier Science B.V. All rights reserved.