Localization of rate-limiting barrier to penetration of endotoxin through nonkeratinized oral mucosa in vitro.

The penetration of tritiated bacterial endotoxin through nonkeratinized oral mucosal epithelium was studied using an in vitro model system and radioautographic tracer techniques. The basement membrane region of the epithelium was the rate-limiting barrier to penetration, and this barrier effect was independent of the direction and duration of penetration as well as any clearance effects of the vasculature.