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背景 研究已证实莱菔硫烷(SFN)为一种有效的化学预防剂,能调控生物体不同的分子机制以抑制细胞的无序生长.自噬是人体细胞维持自身内环境的生物过程,探讨SFN对晶状体上皮细胞(LECs)生物学行为的影响及其与细胞自噬的关系有助于为后发性白内障(PCO)的预防和靶向治疗提供新的思路.目的 探讨SFN诱导人LECs凋亡的直接作用及其激发细胞自噬潮的作用机制. 方法 将离体24 h内的人供体眼行常规白内障超声乳化手术,取出的完整晶状体囊袋置于含体积分数2％胎牛血清的EMEM中培养,建立PCO囊袋模型.按照分组分别于培养基中添加0(空白对照组)、1、10和100 μmol/L SFN培养30 d,观察各组晶状体囊袋上细胞的生长情况,并采用免疫荧光技术检测细胞中F-actin和Vimentin的表达.用含5％胎牛血清的EMEM培养晶状体上皮细胞系FHL124,将培养的细胞分为空白对照组1、10、30和100 μmol/L SFN处理组,行乳酸脱氢酶(LDH)释放试验以测定各组细胞LDH释放的百分率;采用划痕试验检测各组细胞划痕面积的变化以评估细胞迁移能力;透射电子显微镜下观察各组细胞中自噬囊泡的超微结构及数量;采用Western blot法检测SFN组、SFN+3-MA组和3-MA处理的细胞自噬活动特异蛋白LC3的相对表达. 结果 各不同质量浓度SFN组晶状体囊袋上细胞覆盖率总体比较差异有统计学意义(F=48.57,P＜0.01).10 μmol/L SFN组明显低于空白对照组和1μmol/L SFN组.免疫荧光检测技术表明空白对照组增生细胞中F-actin和Vimentin染色阳性,增生的细胞排列致密,随着SFN质量浓度升高,F-actin和Vimentin阳性细胞密度下降,100 μmol/L SFN组未发现F-actin和Vimentin阳性细胞.空白对照组及1、10、30和100 μmol/L SFN组细胞LDH释放量(A值)分别为0.19±0.03、0.39±0.06、0.56±0.07、0.68 ±0.08和0.89±0.09,其中10、30、100 μmol/L SFN组细胞LDH释放量均明显高于空白对照组,随着SFN质量浓度升高,细胞LDH释放量逐渐增加,均明显高于其相邻的低质量浓度组,差异均有统计学意义(均P＜0.01).随着SFN质量浓度的升高,划痕面积减少率呈下降趋势,10、30、100 μmol/L随着SFN质量浓度升高,划痕面积的减少均明显低于其相邻的低质量浓度组,差异均有统计学意义(均P＜0.05).空白对照组、SFN组、SFN+3-MA组和3-MA细胞中LC3-Ⅱ蛋白表达的灰度值分别为0.423±0.003、14.543±0.024、0.668±0.024和0.576±0.056,SFN+3-MA和3-MA组LC3-Ⅱ蛋白表达的灰度值均明显低于SFN组,差异均有统计学意义(均P＜0.01).空白对照组及1、10和100 μmol/L SFN组间自噬小体数量分别为4.07 ±0.32、4.13±0.34、9.21 ±0.53和21.02±1.34,其中10和100 μmol/L SFN组细胞中自噬小体数量均明显高于空白对照组及1μmol/L SFN组,差异均有统计学意义(均P＜0.01). 结论 SFN可以激发人LECs自噬潮,从而抑制离体人晶状体囊上LECs的增生,促进LECs的死亡.本研究结果有望成为预防和治疗PCO的新药.

Background Sulforaphane (SFN) is an effective chemopreventive agent and can regulate the biological molecular mechanisms to inhibit the overgrowth of cells.Autophagy is a biological process of maintaining cellular internal environment.Understanding the affection of SFN to biological behavior of human lens epithelial cells (LECs) and the association of SFN with autophagy is helpful for the prevention and target treatment of posterior capsule opacification (PCO).Objective This study was to investigate the eradication effeccts of SFN on residual lens cell population in vitro posterior capsule opacification (PCO) model and evaluate the mechanism of SFN-induced cell death.Methods In vitro human capsular bag models were generated from fresh donor eyes by phacoemulsification and were cultured in EMEM containing 2％ fetal bovine serum (FBS).Different concentrations of SFN (0,1,10 and 100 μ mol) were added in the medium for 30 days respectively according to grouping,and the growth of LECs was observed by optical microscope and immunofluorescence technique.FHL124,a human LEC line,was cultured with EMEM containing 5％ FBS and divided into 0,1,10,30 and 100 μmol SFN groups.Lactate dehydrogenase (LDH) release rate in the medium was detected to evaluate cell damage/death.The migration of the cells on capsular bags was assessed by scratch test.The ultrastructure and number of autophagosomes were examined under the transmission electron microscope.The expression of LC3 in the cells were detected using Western blot in the presence or absence of autophagy inhibitors.Results The cell coverage rates on the capsular bags were significantly lower in the 10 and 100 μ mol/L SFN groups than those in the 0 and 1 μmol/L SFN groups,with a statistically significant difference among the groups (F =48.57,P ＜ 0.01).Immunofluorescence showed that the density of F-actin-and Vimentin-positive cells was evidently decreased in the 10 and 100 μmol/L SFN groups compared with 0 and 1 μ mol/L SFN groups.The releasing levels of LDH (absorbancy) were 0.19± 0.03,0.39±0.06,0.56±0.07,0.68±0.08 and 0.89±0.09 in the 0,1,10,30 and 100 μ mol/L SFN groups,respectively,and the releasing level of LDH was gradually increased in the 10 and 100 μ mol/L SFN groups in comparison with the 1 μmol/LSFN group (all at P＜0.01).With the increase of SFN concentration,the reduction rate of scratched area decreased with the increase of SFN concentration,and the decrease of scratch area was significantly lower than that of adjacent low mass concentration group and the differences were statistically significant (P＜0.05).The relative expressions of LC3-Ⅱ protein were 0.423±0.003,14.543±0.024,0.668±0.024 and 0.576±0.056 in the blank control group,SFN group,SFN + 3-MA group and 3-MA group,respectively,and the relative expressions of LC3-Ⅱ protein were significantly lower in the SFN+3-MA group and 3-MA group than those in the SFN group (all at P＜0.01).The number of autophagosomes was 4.07±0.32,4.13±0.34,9.21 ±0.53 and 21.02± 1.34 in the blank control group,and 1,10,100 μmol/L SFN groups,and the number of autophagosomes in the 10 and 100 μ mol/L SFN groups was significantly higher than that in the blank control group and 1 μmol/L SFN group (all at P＜0.01).Conclusions SFN mediates LECs death by promoting autophagy in ex vivo capsular bags,and SFN may be a novel agent of potential chemopreventive and target treatment for PCO.