Objective:

2

To investigate the effect of Chang'an Ⅱ Decoction (肠安Ⅱ号方)-containing serum on intestinal epithelial barrier dysfunction in rats.

Methods:

2

Tumor necrosis factor (TNF)-α-induced injury of Caco-2 monolayers were established as an inflammatory model of human intestinal epithelium. Caco-2 monolayers were treated with blank serum and Chang'an Ⅱ Decoction-containing serum that obtained from the rats which were treated with distilled water and Chang'an Ⅱ Decoction intragastrically at doses of 0.49

0.98

1.96 g/(kg•d) for 1 week

respectively. After preparation of containing serum

cells were divided into the normal group

the model group

the Chang'an Ⅱ-H

M

and L groups (treated with 30 ng/mL TNF-α and medium plus 10% high

middle-

and low-doses Chang'an Ⅱ serum

respectively). Epithelial barrier function was assessed by transepithelial electrical resistance (TER) and permeability of fluorescein isothiocyanate (FITC)-labeled dextran. Transmission electron microscopy was used to observe the ultrastructure of tight junctions (TJs). Immunofluorescence of zonula occludens-1 (ZO-1)

claudin-1 and nuclear transcription factor-kappa p65 (NF-κBp65) were measured to determine the protein distribution. The mRNA expression of myosin light chain kinase (MLCK) was measured by real-time polymerase chain reaction. The expression levels of MLCK

myosin light chain (MLC) and p-MLC were determined by Western blot.

Results:

2

Chang'an Ⅱ Decoction-containing serum significantly attenuated the TER and paracellular permeability induced by TNF-α. It alleviated TNF-α-induced morphological alterations in TJ proteins. The increases in MLCK mRNA and MLCK

MLC and p-MLC protein expressions induced by TNF-α were significantly inhibited in the Chang'an Ⅱ-H group. Additionally

Chang'an Ⅱ Decoction significantly attenuated translocation of NF-κBp65 into the nucleus.

Conclusion:

2

High-dose Chang'an Ⅱ-containing serum attenuates TNF-α-induced intestinal barrier dysfunction. The underlying mechanism may be involved in inhibiting the MLCK-MLC phosphorylation signaling pathway mediated by NF-κBp65.