姜黄素诱导牛晶状体上皮细胞凋亡的机制

目的探讨天然药物姜黄素对晶状体上皮细胞(LEC)凋亡的诱导效应及其机制。方法通过透射电镜观察姜黄素对体外培养的牛LEC超微结构的影响;采用流式细胞术(FCM)观察姜黄素对LEC的DNA含量及线粒体跨膜电位(AΨm)的影响。结果透射电镜下可观察到姜黄素组LEC呈现核染色质凝聚、固缩、边集、核碎裂等典型的细胞凋亡形态学改变。经FCM检测显示,姜黄素组作用早期(24 h)LEC细胞核的DNA量没有改变,在作用的中、晚期(48、72 h)细胞核内DNA呈现明显的下降趋势,DNA含量显著低于空白对照组(P<0．01);而姜黄素作用早期线粒△Ψm已经开始下降,8 h时△Ψm下降的细胞数占(4．13±0．52)％;作用72 h后达高峰,占(46．91±3．71)％。各期与正常对照组的差异均有统计学意义(P<0．01)。结论姜黄素可通过细胞核和细胞质两种途径诱导LEC凋亡。诱导LEC凋亡可能是姜黄素减少晶状体后囊膜混浊的细胞和分子机制,姜黄素可能成为一种新型的、高效低毒的防治后发性白内障的药物。

Apoptosis of lens epithelial cell induced by curcumin and its mechanism

OBJECTIVE: To investigate the effects of natural drug curcumin (Cur) on apoptosis of lens epithelial cell (LEC) in vitro and its mechanism. METHODS: The bovine LEC were cultured with Cur, the ultrastructure changes were observed under transmission electron microscope (TEM), the DNA content and mitochondrial transmembrane potential (DeltaPsim) changes were studied by flow cytometry (FCM). RESULTS: The typical morphological changes of LEC apoptosis in Cur group detected by TEM included chromatin condensation and aggregation at the periphery of the nucleons and nuclear fragmentation. The DNA content of LEC in Cur group decreased time-dependently. The DNA content was significantly lower than that of the control group (P < 0.01). The DeltaPsim of LEC in Cur group was decreased, appeared in early stage (8 hours) and reached the maximum after 72 hours. The difference of DeltaPsim of LEC between Cur group and the control group was significant (P < 0.01). CONCLUSIONS: Cur can remarkably induce apoptosis of LEC in vitro. Cur induced LEC apoptosis is caused by decrease of DNA content in LEC nucleus. Collapse of DeltaPsim in cytoplasm induced by Cur results in the irreversible apoptosis process of LEC. This is the early event of LEC apoptosis. LEC apoptosis induced by Cur may pass through two pathways: nuclear pathway and cytoplasmic pathway. The apoptosis of LEC induced by Cur may be the cellular and molecular mechanisms of reducing lens posterior capsular opacification by Cur. Cur may become an effective and low toxic medication for the prevention and treatment of after-cataract.