Objective To investigate the protective effects of riluzole, a sustained activator of K2P subfamily member TRAAK potassium channel, in human retinal pigment epithelium (hRPE) cells with oxidative induce by tert-butyl hydroperoxide (t-BHP) in vitro, and to evaluate the possible involvement of K2P in the cytoprotective function of retina degeneration diseases. Methods The third to fifth passage of the primary cultured hRPE cells were used in the following experiments．hRPE cells were divided into seven groups: normal control group.t-BHP (300 mu;mol/L) group.t-BHP with riluzole (2, 5, 10, 20 mu;mol/L) group and riluzole (10 mu;mol/L) group. The apoptosis was measured by the 3(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay, annexinV/PI double staining flow cytometry. Changes of cells and nuclei morphology were observed under a phase contrast microscope and a fluorescence microscope after 4prime;, 6-diamidino-2-phenylindole (DAPI) staining. Immunofluorescence 1abelling was carried out to analysis the expression of TRAAK. Results After 24 hours incubation with 300 mu;mol/L t-BHP, the cells viability decreased to (58.7plusmn;12.2)% as compared to the normal control groups. The cell viability of t-BHP with riluzole group at different concentrations was higher than the t-BHP group, while 10 mu;mol/L riluzole showed maximally protective effect on hRPE death induced by t-BHP（t=4.84.P＜0.05）. Riluzole remarkably decreased pyknotic nucleus and cell swelling when compared with t-BHP group. Morphology of cells was fusiform with the uniform elliptic nuclei in normal and riluzole group. The Results of annexinV/PI double staining flow cytometry showed that ratio of normal cells were （97.6plusmn;1.3）%, （70.3plusmn;7.0）%, （86.9plusmn;5.2）%, （93.9plusmn;1.5）% in normal group.t-BHP group.t-BHP with riluzole group and riluzole group respectively. The ratio significant decreased in t-BHP group when it was compared with the other groups (t=7.53, 4.59, 6.49, respectively.P＜0.05). By contrast with normal group and riluzole group, the ratio of normal cells in t-BHP with riluzole group had no statistical significance（t=2.94, 1.91, respectively.P＞0.05）. Riluzole (10 mu;mol/L) also significantly decreased the ratio of early stage apoptotic cells from (25.50plusmn;8.02)% to (1.20plusmn;0.72)% in t-BHP injured groups （t=7.13，P＜0.05）. The ratio of early stage apoptotic cells significant decreased in t-BHP group when it was compared with the normal group and riluzole group （t=7.07, 5.94, respectively.P＜0.05）. By comparison with normal group and riluzole group, there are no statistical significance in t-BHP with riluzole group（t=0.06, 1.18, respectively.P＞0.05）. The mean gray values of TRAAK expression were 0.040plusmn;0.003, 0.041plusmn;0.001, 0.049plusmn;0.001, 0.055plusmn;0.001 in normal group.t-BHP group.t-BHP with riluzole group and riluzole group respectively. TRAAK density was significantly higher in t-BHP with riluzole group and riluzole group（t=7.40, 12.70, respectively.P＜0.05）. Conclusions Riluzole can protect hRPE cells against oxidative injury-induced cell death at early apoptosis stage. The mechanism may relate to that riluzole can promote the expression of K2P TRAAK potassium channel.
Objective To evaluate the efficacy and safety of intravitreal anti-vascular endothelial growth factor (VEGF) combined with photodynamic therapy (PDT) vs. photodynamic therapy for polypoidal choroidal vasculopathy (PCV).Methods A computerized search was conducted in Pubmed, OVID, Chinese Biological Medicine Database（CBM）,China National Knowledge Infrastructure （CNKI） by using key words ldquo;polypoidal choroidal vasculopathy, photodynamic therapy, intravitreal anti-VEGFrdquo; in Chinese and/or English combined with manually searching of bibliographies of pertinent articles, journals and literature reference proceedings. Randomized controlled trials (RCT) and non-RCT were collected. The search time was ranged from establishment of each database to September, 2011. The search was no 1imitation in language. The best corrected visual acuity (BCVA),resolution and recurring of lesions, decrease or complete resolution of pigment epithelial detachment （PED）,visual extinction or blindness rate,the rate of subretinal hemorrhage were analyzed by RevMan 5.0 software. Results In total, one RCT and four non-RCTs (273 patients) were included in the meta-analysis involving 148 patients in single treatment group and 125 patients in combined treatment group. The results of metaanalyses showed that there was no significant difference between two groups in the mean logarithm of minimal angle of resolution BCVA at six months ［standard mean difference=0.01, 95% confidence interval (CI): -0.12- 0.14,P=0.84］and 12 months ［standard mean difference = 0.04, 95%CI: -0.16-0.25,P=0.69 after treatment. There was no significant difference between two groups in the resolution of lesions ［odds ratio (OR)=1.38,95%CI:0.74-2.55,P=0.31］ at the months after treatment and decrease or complete resolution of PED (OR=0.67,95%CI:0.12-3.69,P=0.65) at 12 months after treatment. There was no significant difference between two groups in the recurring of lesions (OR=1.14, 95% CI:0.58-2.24,P=0.71) and lost of ge; three lines vision or blindness rate (OR=1.20, 95%CI:0.34-4.18,P=0.78) at 12 months after treatment. The rate of subretinal hemorrhage in combine treatment group was significant lower than single treatment group (OR=0.41, 95%CI:0.18 -0.94,P=0.04). Conclusions The incidence of subretinal hemorrhage occurred in patients with PCV after intravitreal anti-VEGF combined with PDT is much lower than that after single PDT.But the visual improvement, resolution of lesions and recurring of lesions of combined treatment need further studied to see if it is better than single PDT.
