Assessment of gut epithelial monolayer barrier function.

Confluent HT-29 monolayers were exposed to SEB or CT (500 ng/ml) in the culture. HRP (20 ng/ml) was added to the apical chamber of transwells. A, the bars indicate the TER of HT-29 monolayers recorded 48 h later. B, the permeability of the epithelial monolayer was carried out in the period of 46 h and 48 h; the bars indicate the HRP levels in the basal chambers of transwells (presented as the percentage of HRP amount added to apical chambers). The data were presented as mean ± SD. *, p<0.01, compared with the group “0”. The X axes of A and B present the treatment of the monolayers; the numbers indicate the concentrations of SEB or CT. sh: HT-29 cells were treated with Cldn2 shRNA. csh: Cells were treated with control shRNA. C, representative electron microscopical images show the uptake of HRP by HT-29 monolayers. Treatments were denoted below each image. The data represent 3 separate experiments.