AIM: To investigate the role of chloride channels in the apoptosis of human poorly differentiated nasopharyngeal carcinoma CNE-2Z cells induced by arsenic trioxide (As2O3).METHODS: The apoptotic rates of CNE-2Z cells induced by As2O3 for 24 h or 48 h were monitored by flow cytometry.The technique of whole-cell patch clamp was used to record the currents activated by As2O3 in the CNE-2Z cells.The inhibition of As2O3-induced apoptosis by chloride channel blocker DIDS in the CNE-2Z cells was analyzed by flow cytometry.RESULTS: As2O3 at 5 μmol/L induced apoptosis of CNE-2Z cells in time-dependent manner.The currents with outward rectification were activated when the cells were exposed to 5 μmol/L As2O3.No obvious time-and voltage-dependent inactivation of the currents was observed.The reverse potential of the currents was close to the equilibrium potential for chloride.The activated currents were inhibited by the chloride channel blockers NPPB and DIDS.The 47% hypertonic solution inhibited the activated currents completely.Chloride channel blocker DIDS inhibited the apoptosis of CNE-2Z cells induced by As2O3.CONCLUSION: As2O3 activates volume-sensitive chloride channels, and chloride channels may play an important role in the apoptosis of CNE-2Z cells induced by As2O3.

[ ABSTRACT] AIM:To investigate the effect of the overexpression of voltage-gated chloride channel family protein 3 ( ClC-3) gene on bones of mice .METHODS: The tail gene detection assay was used to confirm the overexpression of ClC-3.The male FVB mice of three months old were divided into two groups , the wild type ( WT) group and the ClC-3 overexpressed (ClC-3 transgene) group.The body weight, length and weight of the right tibias were measured .The upper and middle parts of the tibias were dissected , decalcified, paraffin-imbed, sectioned and stained with HE staining .The bone morphology metrology was used to analyze the changes of bone structures .The percent trabecular area (%Tb.Ar), trabecular number ( Tb.N) , trabecular width ( Tb.Wi) and trabecular separation ( Tb.Sp) of cancellous bone in the upper part of the tibia were measured.The total tissue area (T.Ar), cortical area (Ct.Ar), percent cortical area (%Ct.Ar), marrow area ( Ma.Ar) and percent marrow area (%Ma.Ar) of the cortical bone in the middle part of the tibia were detec-ted .RESULTS:The wild type mice and the ClC-3-overexpressed mice were verified by the tail gene detection assay . Compared with WT group , the body weight and the length and weight of the tibia were decreased in ClC -3 transgene mice (P<0.05).In the cancellous bones of ClC-3 transgene mice, the%Tb.Ar and Tb.Wi were decreased (P<0.05), the Tb.Sp was increased (P<0.05) and the Tb.N was not significantly changed .In the cortical bones of ClC-3 transgene mice, the T.Ar, Ct.Ar and%Ct.Ar were decreased (P<0.05), the%Ma.Ar was increased (P<0.05), and the Ma. Ar was not significantly changed .CONCLUSION:ClC-3 overexpression may lead to the reduction of the bone mass and the destructure of the cancellous and cortical bones .The results suggest that ClC-3 may be involved in the regulation of bone resorption and/or formation.