COMPARISON OF AN IN-VITRO SKIN MODEL TO NORMAL HUMAN SKIN FOR DERMATOLOGICAL RESEARCH

EpiDerm(TM), an in vitro human skin equivalent (HSE), was compared to normal human breast skin (NHS) to morphologically and biochemically as sess its feasibility for dermatological research. Intralot and interlo t variability was studied in day 0, 1, 2, and 3 in vitro cultures and in day 0, 3, 5, and 7 NHS. For NHS, light microscopy (LM) at day 0 sho wed stratified epidermis which exhibited an increase in vacuoles and d ark basal cells as storage increased to 3, 5, and 7 days. Transmission electron microscopy (TEM) revealed typical organelles in the epidermi s and a convoluted basement membrane at day 0. With increased storage, vacuoles and paranuclear clefts became numerous, necrosis increased, tonofilaments became less organized, and overall cellular integrity de creased. Biochemical data showed consistent MTT and glucose utilizatio n (GU) through day 5, while lactate production decreased to 75% by day 3. By LM, day 0 HSE consisted of a thick, compact, stratum corneum th at sent projections between the stratum granulosum cells. By TEM, the configuration, organization, differentiation, distribution, and freque ncy of the organelles differed slightly from NHS. In addition, the bas ement membrane of the HSE was not completely differentiated, and the d ermis was thin and acellular. Although day 1 and 2 cultures showed lit tle change, day 3 exhibited an overall degeneration. Biochemical analy sis showed GU and lactate production decreased through day 3. In concl usion, the EpiDerm(TM) HSE, although exhibiting slight differences, wa s morphologically and biochemically similar to normal human epidermis and may be a valuable model in assessing the toxicology, metabolism, o r pharmacology of nonvesicating compounds. (C) Wiley-Liss, Inc.