Abstract: Objective： To investigate the effect of silver nanoparticles (AgNPs) on hemichannel activity in human skin keratinocytes (HaCaT) and to explore the role of hemichannel in AgNP-induced anti-proliferative effect on HaCaT cells. Methods: HaCaT cells were exposed to 0, 0.1, 0.2, 1.0, 5.0, 10.0, 15.0 and 20.0 μg/cm2 of AgNPs for 24 h and cell viability was assessed by propidium iodide (PI) staining with flow cytometry. Hemichannel activity was examined by ethidium bromide (EB) uptake experiments in cells exposed to AgNPs with and without hemichannel inhibitor carbenoxolone (CBX). Afterward, HaCaT cells were seeded at a low density of 1×104cell /cm2 or a normal density of 4×104cell /cm2 and cultured for 24 h. Cell proliferation was measured by cell counting kit-8 (cck-8) in low-or normal-density cultured cells exposed to AgNPs for 24 h with and without 100 μmol/L CBX. Results: Cell viability showed no significant differences between the control and AgNP-exposed groups with the concentration less than 10 μg/cm2. Exposure to AgNPs increased EB uptake in a time- and dose-dependent manner in HaCaT cells and EB fluoresce density was increased to 116.67%, 124.85% and 139.53% of the control after exposure to 10 μg/cm2 AgNPs for 2 h, 12 h and 24 h. After being treated with 25, 50 and 100 μmol/L CBX, 10 μg/cm2 AgNP-induced increase in EB uptake was significantly reduced in HaCaT cells (P<0.01). The cellular proliferation rate was increased inlow-and normal-density cultured cells after AgNPs exposure with 100 μmol/L CBX. After being treated with 100 μmol/L CBX, 10 μg/cm2 AgNP-induced anti-proliferation in low-density cultured cells was significantly restrained (P<0.01). Conclusion: AgNPs could enhance hemichannel activity of HaCaT cells. Hemichannel activation was involved in AgNP-induced anti-proliferative effect.

Key words: Silver nanoparticles, Hemichannel, Cell proliferation