chloride channel protein 2 prevents glutamate-induced apoptosis in retinal ganglion cells

objective(s): the purpose of this study was to investigate the role of chloride channel protein 2 (clc-2) in glutamate-induced apoptosis in the retinal ganglion cell line (rgc-5). materials and methods: rgc-5 cells were treated with 1 mm glutamate for 24 hr. the expression of clc-2, bax, and bcl-2 was detected by western blot analysis. cell survival and apoptosis were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (mtt) and flow cytometry assays, respectively. caspase-3 and -9 activities were determined by a colorimetric assay. the roles of clc-2 in glutamate-induced apoptosis were examined by using clc-2 complementary deoxyribonucleic acid (cdna) and small inference ribonucleic acid (rna) transfection technology. results: overexpression of clc-2 in rgc-5 cells significantly decreased glutamate-induced apoptosis and increased cell viability, whereas silencing of clc-2 with short hairpin (sh) rna produced opposite effects. clc-2 overexpression increased the expression of bcl-2, decreased the expression of bax, and decreased caspase-3 and -9 activation in rgc-5 cells treated with glutamate, but silencing of clc-2 produced opposite effects. conclusion: our data suggest that clc-2 chloride channels might play a protective role in glutamate-induced apoptosis in retinal ganglion cells via the mitochondria-dependent apoptosis pathway.