NO INCREASE IN BLOOD-BRAIN-BARRIER PERMEABILITY AFTER INTRAPERITONEALINJECTION OF ENDOTOXIN IN THE RAT

Reactions mediated by the brain are part of the response to intraperit oneal administration of endotoxin, a model of gram-negative bacterial infection. To test the hypothesis that a compromised blood-brain barri er (BBB) may contribute to these reactions, the integrity of the BBB w as measured following lipopolysaccharide administration. Rats received intraperitoneal injections of 50 mu g/kg or 2 mg/kg of endotoxin. Bra in uptake of a macromolecular vascular marker, H-3-labelled rat serum albumin, and of a poorly permeable low molecular weight substance, [C- 14]sucrose, was then measured with the intravenous bolus injection met hod. Compared to controls, neither dose of endotoxin affected the BBB permeability for these tracers. This was true when brain uptake was me asured 5 min or 2 h after lipopolysaccharide injection. It is conclude d that intraperitoneal endotoxin even at a high dose does not acutely disrupt the BBB. (C) 1998 Elsevier Science B.V. All rights reserved.