Abstract: Objective To investigate the effects of trivalent arsenicals on cell proliferation and induction of apoptosis in human epidermal keratinocytes. Methods Human benign epidermal keratinocytes (cell line HaCaT), human epidermal carcinoma cells(cell line A431) were cultured. After treatment with arsenous acid, inhibition of cellular growth was determined by measuring MTT dye absorption of living cells.Apoptosis was assessed with respect to morphological changes by light and electron microscopy and to cell cycle distribution by flow cytometry. An nexin-V binding assay was used to detect the early stage of apoptosis. Results With concentrations ranging from 0.5 to 10 靘ol/L, arsenous acid significantly inhibited the proliferation of HaCaT cells in a dose-and time-dependent manner. By light and electron microscopy, morphological changes revealed characteristics of apoptosis. But A431 cells showed no obvious change. DNA flow cytometric an alysis indicated that arsenousacid induced an arrest in G₂M phase and sub-G₁p hase in HaCaT compared with A431 cells. The green flurorescence indicated early stage of apoptosis in HaCaT cells by annexin-V binding assay. Conclusion Arsenous acid may inhibit the proliferation of HaCaT cells and induce apoptosis, but does not affect A431 cell line obviously, which suggests that HaCaT cells are more sensitive to arsenous acid compared with A431 cells.

Key words: Arsenites, Keratinocytes, Apoptosis