车前子对晶状体上皮细胞氧化损伤防护作用的信号转导机制

目的:研究车前子对过氧化氢(H₂O₂)所致氧化损伤的晶状体上皮细胞(LEC)内钙(Ca²⁺)、环磷酸腺苷(cAMP)、环磷酸鸟苷(cGMP)的影响,探讨归肝经明目中药防治白内障的细胞信号转导机制。方法:将H₂O₂与传代培养的牛LEC共同孵育复制氧化损伤模型,同时加入车前子水提取液孵育后,用四甲基偶氮唑蓝法(MTT)检测LEC活性,用荧光分光光度法检测LEC内钙离子的浓度(Ca²⁺]_i)、放射免疫分析法检测LEC内cAMP和cGMP含量,并探讨不同浓度的车前子及孵育12、24、36h的影响。结果:H₂O₂组LEC活性下降,车前子可明显增强氧化损伤的LEC活性(P<0.01),呈浓度依赖关系和时间依赖关系。H₂O₂组LEC的Ca²⁺]_i升高,车前子可显著降低由氧化损伤所致的LEC的Ca²⁺]_i的升高(P<0.01),呈时间-效应关系。H₂O₂组LEC的cAMP浓度升高、cGMP浓度下降,车前子可使氧化损伤的LEC的cAMP水平显著降低(P<0.01)、cGMP水平显著升高(P<0.01),也呈时间-效应关系。结论:车前子可明显抑制LEC氧化损伤及凋亡,Ca²⁺]_i、cAMP和cGMP信号系统及其相互作用调节生物学效应可能是其细胞和分子生物学的主要作用机制。

Protective effect of semen plantaginis on oxidative damage of lens epithelial cell and its mechanism of signal transduction

AIM: To investigate the effect of semen plantaginis(SP)on Ca²⁺]_i, cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP)of lens epithelial cell (LEC)damaged by H₂O₂ and the mechanism of calcium signal transduction.METHODS: Sub-cultured bovine LECs were incubated with H₂O₂ and deferent concentrations of SP(8, 4, 2mg/mL)for 12, 24 and 36 h respectively.The LEC activities were observed by methyl thiazolyl tetrazolium assay (MTT).LEC Ca²⁺]_i were detected by spectrofluorophotometer.Intracellular cAMP and cGMP of LEC were determined by radioimmunoassay.And the effects of different concentrations of SP and incubation for different times of 12, 24, 36 h were studied.RESULTS: The activities of LEC increased in deferent concentrations of SP groups compared with those in H₂O₂ group(P<0.01), which showed dosedependent and time-dependent manner.The Ca²⁺]_i of LEC decreased in SP groups compared with those in H₂O₂ group(P<0.01), which showed time-dependent manner.The cAMP concentration of LEC decreased and the cGMP concentration of LEC increased in SP groups compared with those in H₂O₂ group (P< 0.01), which showed time-dependent manner.CONCLUSION: SP can protect LEC against oxidative damages and increase activities of LEC.The Ca²⁺]_i, cAMP and cGMP signal transduction system and the cross-talk may be the mechanisms of SP preventing and delaying the cataract formation.