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.
Huber
Jason D
JD
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.
Hau
Vincent S
VS
Mark
Karen S
KS
Brown
Rachel C
RC
Campos
Chris R
CR
Davis
Thomas P
TP
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