RESUMO
Background The proliferation and migration of vascular endothelial cells is a primary link during angiogenesis.Studies showed that heat shock protein B6 (HspB6) promotes the secretion of multiple angiogenesis-related factors and therefore leads to neovascularization.Understanding the effects of neutralizing HspB6 antibody on the biological behavior of human choroidal vascular endothelial cells has an important significance in the target treatment of choroidal neovacularization diseases.Objective This study was to address the role and mechanism of neutralizing HspB6 antibody in tube formation of human choroidal vascular endothelial cells.Methods Human choroidal vascular endothelial cell line was normally cultured and harvested for total RNA extraction.Expressions of HspB6 mRNA and protein in human choroidal vascular endothelial cells were detected by reverse transcription PCR (RT-PCR) and flow cytometry (FCM).The cells were seeded on 96-well plate covered with matrigel at the density of 2×104/hole.Then the neutralizing HspB6 antibody at the concentration of 100 μg/Land 500 μg/L was added into the medium respectively,and the control cells were set without the addition of HspB6 antibody.The number of capillary tubes was calculated 12 hours after culture by three-dimensional matrigel assay.In addition,0,50,100,500 μg/L of neutralizing HspB6 antibody were added into the cell medium separately for 24hours,cell counting kit-8 (CCK-8) method was employed to assay the inhibitory rate(IR) of the cells.Transwell test was used to count the cell number across chamber membrane for the evaluation of migration ability of the cells.The apoptosis of the cells was assayed by FCM.Results Both HspB6 mRNA and protein were expressed on human choroidal vascular endothelial cells.The number of capillary tube formation of human choroidal vascular endothelial cells was (67.25±5.75),(60.39±6.41) and (39.76±10.73) /field in the 0,100 and 500 μg/L neutralizing HspB6 antibody groups,with significant difference among them (F =10.210,P =0.012),and the tube number was significantly less in the 500 μg/L neutralizing HspB6 antibody group compared with 0 μg/L neutralizing HspB6 group (P =0.005).The IR of neutralizing HspB6 antibody to the cellular proliferation and migration was enhanced with the increases of concentration and time lapse(Fconcentration =7.485,P =0.002 ; Ftime =16.684,P =0.001).The number of the cells through Transwell chamber membrane was 14.0 ± 2.5,11.1 ± 0.8,6.6 ± 0.1,6.7 ± 0.2 in the 0,50,100,500 μg/L neutralizing HspB6 antibody group respectively,and that in the 100 μg/L and 500 μg/L neutralizing HspB6 antibody group was lessened in comparison with the 0 μg/L neutralizing HspB6 antibody group(both at P=0.000).The apoptosis rate of the cells was (22.73 ± 2.53)％ in the neutralizing HspB6 antibody group,which was significantly lower than (13.33±2.08) ％ of the control group (t=4.967,P=0.008).Conclusions Neutralizing HspB6 antibody inhibits capillary tube formation of human choroidal endothelial cells in vitro in dose-and timedependent manner,probably through suppressing the proliferation and migration and promoting the apoptosis of choroidal endothelial cells.