The effect of topical analgesics on ex vivo skin growth and human keratinocyte and fibroblast behavior.

The application of topical analgesics to the donor site of split thickness skin grafts has been proven to be an effective method of pain management but little is known about their effects on wound reepithelialization. This study compares the effect of four analgesics on human keratinocytes and fibroblasts and whole skin explants in vitro to determine whether epithelial cell behavior is affected by topical analgesics. The effect of diclofenac, bupivacaine, lidocaine, and ketorolac was studied at concentrations between 10 mM and 1 nM. The effect on epithelial growth was measured using an ex vivo skin explant model. In addition, cell proliferation, and cytotoxicity were measured in cultured primary human keratinocytes and fibroblasts. Epithelial growth from the explant model was most inhibited by diclofenac with a significant reduction at 100 microM (p=>0.001). Diclofenac also exhibited the strongest inhibitory effect on cell proliferation especially in keratinocytes. Ketorolac was the most cytotoxic. Bupivacaine showed cytotoxicity in a dose-dependent manner with only the very highest concentrations having a significant inhibitory effect. Lidocaine showed no evidence of cytotoxicity at the concentrations tested in either the in vitro cell studies or the ex vivo explant model. Topical analgesics alter keratinocyte and fibroblast behavior and such inhibition may affect wound healing.