Liu Ran, Yang Shao-Hua, Perez Evelyn, Yi Kun Don, Wu Samuel S, Eberst Kathleen, Prokai Laszlo, Prokai-Tatrai Katalin, Cai Zu Yun, Covey Douglas F, Day Arthur L, Simpkins James W
Department of Pharmacology and Neuroscience, Health Science Center at Fort Worth, University of North Texas, 76107, USA.
Stroke. 2002 Oct;33(10):2485-91. doi: 10.1161/01.str.0000030317.43597.c8.
Although estrogens are neuroprotective, hormonal effects limit their clinical application. Estrogen analogues with neuroprotective function but lacking hormonal properties would be more attractive. The present study was undertaken to determine the neuroprotective effects of a novel 2-adamantyl estrogen analogue, ZYC3.
Cytotoxicity was induced in HT-22 cells by 10 mmol/L glutamate. 17beta-Estradiol (E2) or ZYC3 was added immediately before the exposure to glutamate. Cell viability was determined by calcein assay. The binding of E2 and ZYC3 to human alpha (ERalpha) and beta (ERbeta) estrogen receptors was determined by ligand competition binding assay. Ischemia/reperfusion injury was induced by temporary middle cerebral artery occlusion (MCAO). E2 or ZYC3 (100 microg/kg) was administered 2 hours or immediately before MCAO, respectively. Infarct volume was determined by 2,3,5-triphenyltetrazolium chloride staining. Cerebral blood flow was recorded during and within 30 minutes after MCAO by a hydrogen clearance method.
ZYC3 significantly decreased toxicity of glutamate with a potency 10-fold that of E2. ZYC3 did not bind to either ERalpha or ERbeta. Infarct volume was significantly reduced to 122.4+/-17.6 and 83.1+/-19.3 mm(3) in E2 and ZYC3 groups, respectively, compared with 252.6+/-15.6 mm(3) in the ovariectomized group. During MCAO, both E2 and ZYC3 significantly increased cerebral blood flow in the nonischemic side, while no significant differences were found in the ischemic side. However, E2 and ZYC3 significantly increased cerebral blood flow in both sides within 30 minutes after reperfusion.
Our study shows that ZYC3, a non-receptor-binding estrogen analogue, possesses both neuroprotective and vasoactive effects, which offers the possibility of clinical application for stroke without the side effects of estrogens. It also suggests that both the neuroprotective and vasoactive effects of estrogen are receptor independent.
尽管雌激素具有神经保护作用，但其激素效应限制了其临床应用。具有神经保护功能但缺乏激素特性的雌激素类似物可能更具吸引力。本研究旨在确定一种新型2-金刚烷基雌激素类似物ZYC3的神经保护作用。
用10 mmol/L谷氨酸诱导HT-22细胞产生细胞毒性。在暴露于谷氨酸之前立即加入17β-雌二醇（E2）或ZYC3。通过钙黄绿素测定法测定细胞活力。通过配体竞争结合试验测定E2和ZYC3与人α（ERα）和β（ERβ）雌激素受体的结合。通过短暂大脑中动脉闭塞（MCAO）诱导缺血/再灌注损伤。分别在MCAO前2小时或立即给予E2或ZYC3（100μg/kg）。通过2,3,5-三苯基氯化四氮唑染色测定梗死体积。通过氢清除法在MCAO期间及MCAO后30分钟内记录脑血流量。
ZYC3显著降低谷氨酸的毒性，其效力是E2的10倍。ZYC3不与ERα或ERβ结合。与去卵巢组的252.6±15.6 mm³相比，E2组和ZYC3组的梗死体积分别显著减小至122.4±17.6和83.1±19.3 mm³。在MCAO期间，E2和ZYC3均显著增加非缺血侧的脑血流量，而缺血侧未发现显著差异。然而，E2和ZYC3在再灌注后30分钟内均显著增加双侧脑血流量。
我们的研究表明，ZYC3这种不与受体结合的雌激素类似物具有神经保护和血管活性作用，这为中风的临床应用提供了可能性，且无雌激素的副作用。这也表明雌激素的神经保护和血管活性作用均不依赖于受体。
