Inhibitory effect of apigenin on human Tenon capsule fibroblasts

Background Proliferation of the human Tenon capsule fibroblasts(HTFs) is a main cause of failure of filtering surgery.To search the drug of inhibiting the growth of the HTFs is essential for the improvement of successful rate of filtering surgery.Objective The aim of this study was to investigate the inhibitory effect of apigenin on HTFs and its mechanism.Methods Human Tenon capsular tissue was obtained during the strabismus correction surgery.HTFs was primarily cultured using explant method and identified using vimentin by immunochemistry.The 3-5 generation of cells were incubated to 96-well plate.Apigenin of 0,20,40,80,160 μmol/L was added into the medium,respectively,for 24,48,72 hours,and the proliferation of HTFs was detected by sulfonyl chloride (SRB) at the wavelength of 560 nm (A560).Bromodeoxyuridine (BrdU) of 10 μg/L was added to culture the cells for 48 hours to calculate the labeling rate of BrdU.The morphology of the cells was observed using Hoechst 33258 staining,and apoptosis and cells cycle were evaluated by flow cytometry.Results Cultured cells grew well with the positive response for vimentin,showing the green fluorescence in cytoplasm.SRB assay showed that the A560 value was gradually declined with the increase of the dosage of apigenin and prolong of time (Fgroup =480.306,P =0.000 ; Ftime =555.144,P =0.000).The labeling rate after 0,40,80 μmol/L apigenin acted for 48 hours was (87.860 ±0.632)％,(61.520±4.306)％ and (23.480±4.472)％,showing a significant difference among the three groups (F =299.347,P =0.000).The labeling rate of HTFs for BrdU was significantly decreased in the 40 and 80 μmol/L apigenin groups compared with the 0 μmol/L apigenin group (P＜0.05).Hoechse 33258 staining found that the number of the HTFs was gradually decreased and the cell number of karyopyknosis and nuclear deformation was increased with the increase of apigenin dosage.Percentage of cells in G0/G1 phase were raised and that in S and G2/M phase were declined in the higher dosage apigenin group,with a significant difference among the different groups (FG0/G1 =58.621,P=0.000;Fs =32.357,P=0.001 ;FG2/M =83.998,P=0.000).In the 72nd hour after acted by 0,40,80,160 μmol/L apigenin,the apoptosis rate of HTFs was (4.77±0.21) ％,(13.24±1.35)％,(18.33±1.86) ％,(31.58 ± 2.77) ％,respectively,with a statistically significant difference among the four groups (F =204.791,P＜0.05).Conclusions Apigenin restrains the growth of HTFs by evoking G0/G1 cell cycle arrest and inducing apoptosis in a dosage-and time-dependent manner. Key words: Apigenin;  Human Tenon capsule fibroblast;  Apoptosis