Full-thickness human skin explants for testing the toxicity of topically applied chemicals.
This report describes a model organ-culture system for testing the toxicity of chemical substances that are topically applied to human skin. In this system, the viable keratinocytes in the full-thickness skin explants are protected by the same keratinized layer as skin remaining on the donor, and toxicity can be assessed microscopically and/or biochemically. The human skin specimens were discards from a variety of surgical procedures. They were cut into full-thickness 1.0-cm2 explants, and briefly exposed to the military vesicant sulfur mustard (SM), which was used as a model toxicant. The explants were then organ cultured in small Petri dishes for 24 h at 36 degrees C. In the 0.03-1.0% dosage range, a straight-line dose-response relationship occurred between the concentration of SM applied and the number of paranuclear vacuoles seen histologically in the epidermis. Within the same SM dosage range, there was also a proportional decrease in 14C-leucine incorporation by the explants. Thus, the number of paranuclear vacuoles reflected decreases in protein synthesis by the injured epidermal cells. The epidermis of full-thickness untreated (control) human skin explants usually remained viable for 7 d when stored at 4 degrees C in culture medium. During storage, a relatively small number of paranuclear vacuoles developed within the epidermis, but the explants were still quite satisfactory for testing SM toxicity. Incubation (for 4 or 24 h at 36 degrees C) of such control skin explants reduced (often by 50%) the small number of paranuclear vacuoles produced during 4-7 d of storage. This reduction was probably caused by autolysis of many of the vacuolated cells. Two types of paranuclear vacuoles could be identified by both light and electron microscopy: a storage type and a toxicant type. The storage type seemed to be caused by autolysis of cell components. The toxicant type seemed to be caused by an invagination of the plasma membrane. Only toxicant-type vacuoles increased appreciably in number when skin explants were exposed to mustard, and to other toxicants.
Nakamura
M
M
Department of Environmental Health Sciences, School of Hygiene and Public Health, Johns Hopkins University, Baltimore, Maryland.
Rikimaru
T
T
Yano
T
T
Moore
K G
KG
Pula
P J
PJ
Schofield
B H
BH
Dannenberg
A M
AM
D000287:Administration, Topical; D001386:Azides / Q000494:pharmacology; D002250:Carbon Radioisotopes; D003513:Cycloheximide / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007930:Leucine / Q000378:metabolism; D009150:Mustard Compounds / Q000633:toxicity*; D009151:Mustard Gas / Q000008:administration & dosage / Q000633:toxicity*; D009924:Organ Culture Techniques; D014176:Protein Biosynthesis; D012867:Skin / Q000187:drug effects* / Q000648:ultrastructure; D013696:Temperature; D014022:Tissue Survival / Q000187:drug effects; D014617:Vacuoles / Q000187:drug effects
D001386:Azides; D002250:Carbon Radioisotopes; D009150:Mustard Compounds; D003513:Cycloheximide; D007930:Leucine; D009151:Mustard Gas