MODULATION OF CYTOKINE MESSAGE IN THE EPIDERM IN VITRO SKIN MODEL FOLLOWING TREATMENT WITH CONTACT ALLERGENS AND SKIN IRRITANTS.

Previous studies have demonstrated that EpiDerm™ (MatTek Corporation) in vitro skin model constitutively expresses message for several cytokines (Limardi et al., 1996 JID 106, 939). The objective of research presented here is to assess the ability of irritants and contact allergens to modulate cytokine message in the EpiDerm model. Total RNA was isolated at 2 and 6 hours following topical application of chemicals. Cytokine message was evaluated using RT-PCR and liquid hybridization, with normalization to the housekeeping gene, G3PDH. Two different irritants were evaluated in these studies benzalkonium chloride (BC; quaternary amine) and nonanoic acid (NA; acid) as well as two moderate to strong contact allergens, TNCB and oxazolone (OXA). In summary, each chemical produced a unique pattern of changes in cytokine message in the EpiDerm that were time dependent and, in some cases, concentration-dependent. Similar studies were previously done using another in vitro human skin model Skin2, from Advanced Tissue Sciences (Sikorski, et al., 1996, JID 106, 939). Skin2 consists of both stratified epithelial cells and fibroblasts while the EpiDerm consists of stratified epithelial cells. EpiDerm was found to have generally much lower levels of constitutive cytokine message than Skin2 which may be due to lack of a fibroblast layer. For both EpiDerm and Skin2, (1) similar concentrations of chemicals were optimal in both systems, (2) each chemical produced a unique pattern of changes in cytokine message that was time- and concentration-dependent (some similarities were seen between these two systems for certain chemicals), (3) none of the cytokines studied were found to specifically identify a contact allergen and differentiate it from an irritant and (4) further evaluation of TNF-α message is suggested as it may be a potential marker for irritants in both skin models.

Allergens, Benzalkonium chloride, Contact allergens, Cutaneous irritancy, Cutaneous irritation, Cutaneous toxicity, Cytokines, Dermal irritancy, Dermal irritancy testing, Dermal irritation, Endpoints, cytokine message, EpiDerm, G3PDH, housekeeping gene, Gene expression, Housekeeping gene, Messenger RNA (mRNA), Nonanoic acid, Oxazolone (OXA), RNA, Isolation of, Skin irritancy, Skin irritants, Skin irritation, Skin models, cultured, TNCB, Trinitrochlorobenzne (TNCB)