1. Department of Animal Science and Technology, National Taiwan University, Taipei 106, Taiwan.
2. Department of Wood Based Materials and Design, National Chiayi University, Chiayi 600, Taiwan.
3. Taiwan Livestock Research Institute, Council of Agriculture, Tainan 712, Taiwan.
* These authors contributed equally to the work.
Background: The mucus integrity and abnormal inflammatory response are the crucial biomarker of inflammatory bowel disease (IBD). Velvet antler (VA) has been used as traditional Chinese medicines for many years. Anti-inflammatory property was demonstrated via suppression of cyclooxygenase-2 and cytokines protein expression. And it has further proved to promote wound healing in streptozotocin-induced diabetic rats model. The aforementioned functionalities of VA extracts may be associated with the treatment of IBD. Thus, the aim of present study was to evaluate the effect of velvet antler water extracts form Formosan Sambar deer (Rusa unicolor swinhoei, SVAE) and red deer (Cervus elaphus, RVAE) on the barrier function and to investigate the possible mechanism using in vitro model.
Methods: Human colonic epithelial cell models (Caco-2) were co-cultured with various concentrations of both SVAE and RVAE (250-500 µg mL-1) in dextran sulfate sodium (DSS)-induced colitis model. Trans-epithelial electrical resistance (TEER) value and the macromolecule permeability of Fluorescein isothiocyanate (FITC)-labeled dextran were measured to evaluate the integrity of monolayer of Caco-2. Western blotting was performed for analysis of protein expressions of occludin, Zonula occludens-1 (ZO-1), claudin-1, claudin-2 and myosin light chain kinase (MLCK). The cytotoxicity was conducted by MTT assay.
Results: Results indicated that both SVAE and RVAE could enhance integrity of monolayer in dextran sulfate sodium (DSS)-induced colonic epithelial cell model (Caco-2) through reducing the decline of trans-epithelial electrical resistance (TEER) and macromolecule permeability at the concentration of 250 μg mL-1. RVAE significantly increased the expression of tight junction proteins (occludin and ZO-1) while SVAE significantly reduced the activity of MLCK (P < 0.05.). Elevated C-C chemokine ligand 20 (CCL20) production suggested that both SVAE and RVAE could enhance the repair of epithelial cell. Besides, MTT assay revealed that both extracts showed no cytotoxicity.
Conclusion: Thus, SVAE and RVAE supplementation may attenuate barrier damage by enhancing the occludin and ZO-1 protein expression, decreasing MLCK expression, promoting the CCL20 production. In the future, animal study is needed for further confirmation.
Keywords: Caco-2 cell model, tight junction proteins, velvet antler.