An in vitro evaluation of the cell toxicity of honey and silver dressings.

OBJECTIVE To establish whether honey and silver-impregnated dressings used by wound-healing practitioners are cytotoxic in vitro to human skin keratinocytes and dermal fibroblasts. METHOD Human keratinocyte and fibroblast tissue cultures were established in vitro. Untreated cultures served as controls (group I). Small dressing implants of monofloral, medicinal honey (L-Mesitran) (group 2) and nanocrystalline silver (Acticoat) (group 3) were placed in test wells and co-cultured with each of the two cell lines. Morphological changes, including cell toxicity, were assessed using inverted microscopy, trypan blue staining and the Rosdy and Clauss cell toxicity scoring system. RESULTS Untreated cultures consisting of both keratinocytes and fibroblasts (group 1) were established in 90% of all cases. In group 2, cultures with honey-impregnated implants, cell proliferation remained present at two and four months. Cell viability remained intact and cell toxicity was not evident at four months after continuous tissue culture. In group 3, marked toxicity was observed with high non-viability staining and cell-scoring counts compared with groups 1 and 2 (p<0.05). This demonstrates that the silver interfered with epidermal cell proliferation and migration, implying that it contains cytotoxic material. CONCLUSION The honey-based product showed excellent cytocompatibility with tissue cell cultures compared with the silver dressing, which demonstrated consistent culture and cell toxicity. Further studies are needed to assess if these comparative in-vitro findings should influence a clinician's choice of wound dressing.