Viability of microvascular endothelial cells to direct exposure of formalin, lambda-carrageenan, and complete Freund's adjuvant.
We investigated three inflammatory agents to establish if these substances elicit a direct effect on the functional and structural integrity of the blood-brain barrier. Cellular cytotoxicity and paracellular permeability were assessed in vitro using primary bovine brain microvascular endothelial cells exposed to formalin, lambda-carrageenan, or complete Freund's adjuvant for 1, 3, or 72 h, respectively. Results showed that only the highest concentration (0.025%) of formalin produced a decrease in cell viability (approximately 34%) and a significant increase in cell permeability to [(14)C]sucrose at 120 min (approximately 137%). Brain perfusion using female Sprague-Dawley rats showed no difference in paracellular permeability to [(14)C]sucrose for any inflammatory agent. Western blot analyses were performed on isolated rat brain microvessels to assess the structural integrity of blood-brain barrier tight junctions. Results indicate that expression of zonula occludens-1, occludin, claudin-1, and actin remain unchanged following intravenous exposure to inflammatory agents. This study confirms that changes seen at the blood-brain barrier following a peripheral inflammation are due to physiological responses to the given inflammatory agent and not to any direct interaction between the inflammatory agent and the brain microvasculature.
Departments of Pharmacology, Physiology, and Neurosciences, The University of Arizona College of Medicine, 1501 N. Campbell Avenue, P.O. Box 24-5050, Tucson, AZ 85724, USA.
Jason D
JD
Huber
Vincent S
VS
Hau
Karen S
KS
Mark
Rachel C
RC
Brown
Chris R
CR
Campos
Thomas P
TP
Davis
D000818:Animals; D001812:Blood-Brain Barrier; D015153:Blotting, Western; D001921:Brain / Q000098:blood supply; D002199:Capillary Permeability / Q000187:drug effects; D002351:Carrageenan / Q000494:pharmacology*; D002417:Cattle; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D005260:Female; D005557:Formaldehyde / Q000494:pharmacology*; D005620:Freund's Adjuvant / Q000494:pharmacology*; D006614:Hindlimb; D066298:In Vitro Techniques; D007249:Inflammation / Q000139:chemically induced / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013395:Sucrose / Q000493:pharmacokinetics; D019108:Tight Junctions / Q000378:metabolism
D008565:Membrane Proteins; D005557:Formaldehyde; D013395:Sucrose; D002351:Carrageenan; D005620:Freund's Adjuvant