The effect of DMBA on hamster cheek pouch mucosa in vitro: constant exposure.

Repeated topical application of DMBA to hamster cheek pouch mucosa in vivo has been shown to cause dysplastic changes and ultimately the development of squamous cell carcinomas in the epithelium. A technique has already been reported whereby neonatal hamster pouch mucosa can be maintained in vitro and dysplastic changes have been described in the epithelium after a single exposure to DMBA. By 35 days in organ culture, these changes disappeared and the epithelium regained its normal organotypic morphology. In this study, the tissue was maintained in vitro in medium containing various concentrations of DMBA for up to 49 days. Dysplastic changes were seen in the epithelium of the explants with some histological evidence of malignant behaviour. These changes were observed throughout the experimental period.