A new way to evaluate the germinative compartment in human epidermis, using [3H]thymidine incorporation and immunoperoxidase staining of 67 K polypeptide.
We have used tritiated thymidine (3HT) labelling and immunoperoxidase staining of 67 K polypeptide in human epidermis to study normal skin before and after irritation induced by application of croton oil (20% and 50% in olive oil). By this double labelling method, it was possible to identify, on the same skin section, DNA-synthesizing nuclei and epidermal cells which contained 67 K polypeptide. Our results clearly indicate that the germinative compartment of normal epidermis is a mixed population comprising basal and adjacent suprabasal cells; as a rule, absence of expression of 67 K polypeptide, which characterizes all basal cells, could not be regarded as a good marker to distinguish the germinative from the differentiating compartments. In mild primary irritation, the ratio of 3HT-labelled undifferentiated cells to keratinizing ones was similar to that observed in normal epidermis. In severe irritation, this homeostatic process was altered, as 3HT-labelled cells were mainly 67 K negative.
D000368:Aged; D002455:Cell Division; D003436:Croton Oil / Q000009:adverse effects; D004247:DNA / Q000096:biosynthesis; D003877:Dermatitis, Contact / Q000209:etiology / Q000503:physiopathology; D005260:Female; D006801:Humans; D007633:Keratins / Q000032:analysis*; D008297:Male; D010455:Peptides / Q000032:analysis*; D012867:Skin / Q000166:cytology* / Q000378:metabolism
D010455:Peptides; D007633:Keratins; D003436:Croton Oil; D004247:DNA