A method to detect areas high in sulfhydryl groups in mouse epithelium.

We have recently modified a non-fluorescent, non-radioactive histochemical method to detect sulfhydryl (S-H) groups in tissues. This method was originally intended to detect chloramphenicol acetyltransferase (CAT) in transgenic mice. Temporal developmental differences in the keratinization of mouse digits can be seen in the staining pattern of the skin about the toes of neonatal mice. The basal cells of the epidermis exposed to the air show intense staining while the epidermis that is still attached to an adjacent toe shows no staining. The degree of S-H presence can be determined by the tissues' resistance to blocking of the S-H groups by iodoacetic acid. Areas that contain very high numbers of S-H groups still show staining following blocking by iodoacetic acid. We have found that this method shows clear differences in the S-H distribution of various epithelium, including skin, hair, nails, and tongue epithelium.