Comparative in vitro cytotoxicity of ethyl acrylate and tripropylene glycol diacrylate to normal human skin and lung cells

Abstract

The potential for occupational exposure to the esters of acrylic acid (acrylates) is considerable, and, thus, requires a greater understanding of the their toxicity. Confluent (70-90%) cultures of normal human epidermal keratinocytes (NHEK), dermal fibroblasts (NHDF). or bronchial epithelium (NHBE) were exposed to the monofunctional ethyl acrylate (EA), the multifunctional tripropylene glycol diacrylate (TPGDA), or TPGDA monomer in a radiation curable lacquer (Lacquer A) at equimolar dosages in order to determine human in vitro cytotoxicity. Viability of the cells after 2-24-h exposure to the representative monofunctional or multifunctional acrylate or solvent control was used to calculate an index of acute cytotoxicity (50% inhibitory dose; ID50) and to determine the shape of the dose-response curves. TPGDA, Lacquer A, and EA were equally cytotoxic (ID50 is approximately equal to 0.1 micromol/cm2) to NHEK at equimolar doses. TPGDA or Lacquer A were more cytotoxic (is approximately equal to 100X) to NHDF or NHBE than EA. Sequential exposure of UV(A) and TPGDA to NHEK indicate the potential for a synergistic cytotoxic response. These findings are consistent with observed decreases in free sulfhydryl groups (e.g., glutathione or cysteine) that parallel the dose-response-related decreases in viability. logether, these data suggest possible differences in toxicity between the monofunctional EA and multifunctional TPGDA to NHEK, NHDF. or NHBE, possibly due to the difference in the number of functional acrylate groups and/or physicochemical differences (e.g., vapor pressure) between the acrylates investigated.