Epithelial exfoliation method for scanning electron microscopy by pronase treatment

Abstract

Some tissues (tongues of mouse, young dog, adult cat and crab-eating macaque, stomach, colon, rectum, gall bladder of guinea pig) fixed in chemical fixative (2.5% paraformaldehyde and 2% glutaraldehyde in cacodylate buffer) were treated in 0.2% or 0.5% pronase for 3-5 days at room temperature (25-27°C) and the epithelial cell layer was able to be removed from the underlying connective tissue layer.
The results obtained by the present pronase method were compared to that obtained from the HCl method (3.5 N-HC1 for 2-3 weeks at room temperature, Kobayashi). After pronase treatment, TEM observation revealed thinness of the basal lamina and the disappearance of actin filaments of muscle fiber.
0.5% or 2% pronase was applied to unfixed gingiva of rat and tongues of rat and guinea pig and the epithelial cell layer was successfully removed from the underlying connective tissue for 30 min -3 h at 37 °C. In view of the results descrided above, it is suggested that the pronase method indicates the possibility of the exfoliation as well as transplantation of the epithelium especially in the oral mucosa.