[Effect of tumor necrosis factor-alpha on the permeability of strial capillary endothelial cells in guinea pig cochlea].

Objective To perform an initial study on possible molecular regulatory mechanisms of TNF-α to the permeability of strial capillary endothelial cells in guinea pig cochlea. Methods Strial capillary endothelial cells in guinea pig cochlea was dissociated and cultureed to establish a model for its permeability in vitro. The animals were divided into TNF-α, TNF-α ＋ L-arginine （ L-Arg ）, TNF-α ＋ NG-minomethyl-L-arginine （L-NMMA） and control groups. In order to measure the alternations of permeation rate, Evans blue was used in different time by different concentrations to detect contents of F-actin in each group under immunofluorescence laser scanning confocal microscope. Results TNF-α increased permeability of stria] capillary endothelial cells notablely, and permeation rate to Evans blue heightened significantly（P < 0. 01 ） and increased under higher concentrations of TNF-α as well as lengthened the durations. Being as a NO donator, L-Arg significantly enhanced the ability of TNF-α which increasing permeability of strial capillary endothelial cells; permeation rate to Evans blue heightened significantly（P < 0. 01 ） , which obviously rose up when the concentration of Evans blue added. L-NMMA, NO inhibitor, was able to weaken the ability of TNF-α which increasing permeability of strial capillary endothelial cells; permeation rate to Evans blue decreased significantly （ P < 0. 01 ） , which obviously fell down when the concentration of L-NMMA added. TNF-α decreased F-actin in strial capillary endothelial cells （P < 0. 01 ） , more TNF-α, less F-actin ; L-Arg could be further the inhibition to F-actin content （ P < 0. 05 ） ; L-NMMA held back the trend （ P < 0. 05 ） . Conclusions TNF-α can increase permeability of strial capillary endothelial cells of guinea pig cochlea. NO may be one of the important molecular regulators to permeability of strial capillary endothelial cells by TNF-α, and changes of F-actin content probably relate to the regulation in these cells. Key words: Stria vascularis; Capillary permeability; Tumor necrosis factor-alpha; Nitricoxide