The effect of turpentine on hamster cheek pouch mucosa: a model of epithelial hyperplasia and hyperkeratosis.

Hamster cheek pouches were painted thrice weekly with 50% v/v turpentine in liquid paraffin over periods ranging from 1 day to 16 weeks. Pouch mucosa was examined histologically for changes and measurements of epithelial thickness were made with a calibrated eyepiece micrometer. An increase in epithelial thickness was first observed 48 hrs. after a single painting and was accompanied by inflammatory changes in both epithelium and connective tissue. Maximal epithelial thickening occurred after 9 weeks of thrice weekly painting. Cheek pouches of animals left without further treatment for up to 1 year following 9 weeks painting were indistinguishable from controls. The epithelial response to treatment with turpentine is that of a reversible benign epithelial hyperplasia with hyperkeratosis.