Zonula occludens toxin increases the permeability of molecular weight markers and chemotherapeutic agents across the bovine brain microvessel endothelial cells

J Pharm Sci. 2003 Feb;92(2):414-23. doi: 10.1002/jps.10310.


The purpose of this study was to examine the ability of Zonula occludens toxin (Zot) to reversibly open tight junctions in bovine brain microvessel endothelial cells (BBMECs) to enhance drug delivery via the paracellular pathway. Transport across BBMEC monolayers was examined for molecular weight markers and chemotherapeutic agents ([(14)C]sucrose, [(14)C]inulin, [(3)H]propranolol, [(3)H]doxorubicin, and [(14)C]paclitaxel) with Zot (0.0-4.0 microg/mL). TEER of monolayers was measured to assess effect and reversibility of Zot. Cell viability of BBMEC in the presence of Zot was assessed by trypan blue exclusion staining. Apparent permeability (P(app)), enhancement ratio (R), and percent increase in transport determined were statistically compared by ANOVA. A significant increase (p < 0.05) in P(app) was observed for the transport of [(14)C]sucrose, [(14)C]inulin, [(3)H]doxorubicin, and [(14)C]paclitaxel at a 4.0 microg/mL concentration of Zot. A significant concentration-dependent decrease in TEER was observed on treatment with Zot with rapid reversal to baseline after removal. Zot (4 micro/ml) was found to be nontoxic to the BBMECs after 2 hours incubation. In conclusion, Zot increased paracellular transport across the BBMEC in a reversible, concentration-dependent manner. Modulation of paracellular transport with Zot may be used to increase the brain permeability of potent central nervous system-active drugs, including anticancer agents.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • ATP Binding Cassette Transporter, Subfamily B, Member 1 / biosynthesis
  • Animals
  • Biological Transport, Active
  • Blood-Brain Barrier / drug effects*
  • Capillaries / drug effects
  • Capillaries / metabolism
  • Cattle
  • Cell Survival / drug effects
  • Cholera Toxin / pharmacology*
  • Endothelium, Vascular / cytology
  • Endothelium, Vascular / drug effects
  • Endothelium, Vascular / metabolism*
  • Fluorescent Dyes
  • In Vitro Techniques
  • Molecular Weight
  • Permeability
  • Rhodamine 123 / metabolism
  • Tight Junctions / metabolism


  • ATP Binding Cassette Transporter, Subfamily B, Member 1
  • Fluorescent Dyes
  • zonula occludens toxin, Vibrio cholerae
  • Rhodamine 123
  • Cholera Toxin