和厚朴酚通过抑制脑MPTP开放和调节PARP-1活性保护全脑缺血的作用研究

目的研究和厚朴酚微乳剂对全脑缺血的影响,探讨其可能的作用机制。方法用断头法制备小鼠急性全脑缺血模型;用分光光度法观察脑线粒体通透性转换孔(MPTP)开放程度;用荧光法测定聚腺苷二磷酸核糖聚合酶-1(PARP-1)活性;用MTT法侧细胞活力。结果和厚朴酚(7～70μg.kg-1)单次静注可剂量依赖地增加小鼠断头后喘息次数、降低小鼠脑匀浆液中乳酸的含量,升高脑匀浆液中ATP的含量。和厚朴酚(2.5μmol.L-1～10μmol.L-1)可浓度依赖地降低脑组织MPTP的开放,它可浓度依赖地抑制聚腺苷二磷酸核糖聚合酶(PARP-1)活性,其IC50=76.82μmol.L-1,和厚朴酚可明显提高缺氧损伤的PC12细胞存活率。结论和厚朴酚对全脑缺血有保护作用,该作用与其可能减轻缺血状态、抑制能量耗竭和乳酸堆积有关,可能与抑制神经细胞MPTP开放、抑制PARP-1的活性、从而保护神经细胞有关。这些结果为其治疗全脑缺血提供了实验依据。

Honokiol protects brain against global brain ischemia in mice through inhibiting MPTP opening and PARP-1 activity

Aim To investigate the influence of honokiol microemulsion on global ischemia in mice,and explore its potential action mechanism.Methods Global ischemia model in mice was prepared by decapitation,the opening of mitochondria permeability transition pore(MPTP) was detected by spectrophotometry,and the activity of poly-ADP ribose polymerase-1(PARP-1) was determined by fluorometric method.Results Honokiol(7~70 μg·kg-1 bolus iv) significantly increased the breath times of mice,and decreased lactic acid contents and augmented ATP level in brain homogenate in this model.Honokiol(2.5 μmol·L-1~10 μmol·L-1) concentration dependently reduced ΔA520 of mitochondria suspension and inhibited PARP-1 activity.In addition,honokiol enhanced the viability of PC12 cells injured by anoxia.Conclusions This study first discovers the protection of honokiol on global ischemia.The mechanism of its action may be correlated with its alleviating ischemia status,inhibiting energy consumption,reducing MPTP opening and inhibiting PARP-1 over activation,thus protects neural cells.This study has provided experimental basis for its clinical use in global ischemia.