Inter-laboratory Reproducibility of a Three-Dimensional Model of Human Buccal Tissue

Objectives: Human three-dimensional (3D) tissue models of the human oral epithelia are powerful tools for investigating basic biological function in response to various challenges including oral care products and environmental insult. The EpiOral model (MatTek Corporation) is a highly differentiated 3D tissue model exhibiting a buccal phenotype that can provide valuable in vitro data as an early screening tool prior to clinical trials and as an alternative to animal-based studies. To demonstrate inter-laboratory reproducibility of the EpiOral model for broader utility, tissues were exposed to two different inducers by three independent laboratories in three experimental phases. Tissues were exposed to TNF-a/IL-1b to evaluate inflammatory response or 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) to evaluate xenobiotic metabolism using the EpiOral model.
Methods: Following exposure to the TCDD or TNF-a/IL-1b, tissues were evaluated for cytotoxicity (via adenylate kinase release and MTT), CYP450 activity (using a luciferase-based P450 substrate system), pro-inflammatory marker release (via ELISA-based detection of IL-1b, IL-8, IP-10, and MMP-1) and xenobiotic phase I enzyme mRNA expression (using a Phase I Enzyme-specific PCR Array). A total of three experimental phases were conducted to evaluate both inter-phase and inter-laboratory reproducibility.
Results: Significant increases in secreted IL-1b, IL-8, IP-10 and MMP-1 were observed following exposure of oral tissues to inflammatory inducers TNF-a/IL-1b. TCDD exposure resulted in significant increases in the mRNA levels of Phase I metabolism enzymes, CYP1A1 and CYP1B1. Significant increases in CYP1A1/1B1 activity were observed in parallel following TCDD exposure.

Conclusions: The response of the oral epithelial tissue model to inducers of inflammation, specifically TNF-a/IL-1b, were highly reproducible as measured by cytokine release (IL-8 and IL-1beta). In summary, we demonstrate utility of the EpiOral model for evaluation of cytotoxicity, xenobiotic metabolism, gene activation and cytokine profiling in response to various stimuli.