Impact of Hyperosmotic Glycerol on Tighy Junction In Vitro

The tight junction regulates passage of molecules throuth the paracellular spaces. Occludin and claudins are the specific trancmembrance protains present at the tight junction and are believed to regulate the cell barrier functions. To examine the response of the tight junction to hyperosmotic solutions, Ⅰinvestigated the effects of hyperosmotic glycerol on function and protein expression of the tight junction in ECV304 cells. Cell cytotoxicity analysis showed that the high (10%) concentration of glcerol damaged 64.1% of the ECV304 cells (p＜0.001), and this was confirmed morphologically. Treatment with 1%, 2% or 5% glyserol increased the paracellular permeability of fluorescein isothiocyanate (FITC) -labeled dextran by 4.7%, 18.7% and 29.4% (p＜0.05), respectively. In addition, exposure to glycerol at any concentration strongly reduced the expression of occludin, whereas enpression of claudin-1 was affected very slightly. These results suggest that hyperosmotic glycerol would certainly induce the paracellular pathway in vitro and modulate the expression of tight junctional molecules.

claudin-1

glycerol

occludin

transcellular permeability

tight junction