Nakajima Hidemitsu, Kakui Nobukazu, Ohkuma Kunihiro, Ishikawa Midori, Hasegawa Toshifumi
Pharmaceutical Research Center, Meiji Seika Kaisha, Ltd., 760 Moro-oka-cho, Kohoku-ku, Yokohama 222-8567, Japan.
J Pharmacol Exp Ther. 2005 Feb;312(2):472-81. doi: 10.1124/jpet.104.075465. Epub 2004 Oct 1.
We investigated the pharmacological profiles of DR2313 [2-methyl-3,5,7,8-tetrahydrothiopyrano[4,3-d]pyrimidine-4-one], a newly synthesized poly(ADP-ribose) polymerase (PARP) inhibitor, and its neuroprotective effects on ischemic injuries in vitro and in vivo. DR2313 competitively inhibited poly(ADP-ribosyl)ation in nuclear extracts of rat brain in vitro (K(i) = 0.23 microM). Among several NAD(+)-utilizing enzymes, DR2313 was specific for PARP but not selective between PARP-1 and PARP-2. DR2313 also showed excellent profiles in water solubility and rat brain penetrability. In in vitro models of cerebral ischemia, exposure to hydrogen peroxide or glutamate induced cell death with overactivation of PARP, and treatment with DR2313 reduced excessive formation of poly(ADP-ribose) and cell death. In both permanent and transient focal ischemia models in rats, pretreatment with DR2313 (10 mg/kg i.v. bolus and 10 mg/kg/h i.v. infusion for 6 h) significantly reduced the cortical infarct volume. To determine the therapeutic time window of neuroprotection by DR2313, the effect of post-treatment was examined in transient focal ischemia model and compared with that of a free radical scavenger, MCI-186 (3-methyl-1-phenyl-2-pyrazolone-5-one). Pretreatment with MCI-186 (3 mg/kg i.v. bolus and 3 mg/kg/h i.v. infusion for 6 h) significantly reduced the infarct volume, whereas the post-treatment failed to show any effects. In contrast, post-treatment with DR2313 (same regimen) delaying for 2 h after ischemia still prevented the progression of infarction. These results indicate that DR2313 exerts neuroprotective effects via its potent PARP inhibition, even when the treatment is initiated after ischemia. Thus, a PARP inhibitor like DR2313 may be more useful in treating acute stroke than a free radical scavenger.
我们研究了新合成的聚（ADP - 核糖）聚合酶（PARP）抑制剂DR2313 [2 - 甲基 - 3,5,7,8 - 四氢硫代吡喃并[4,3 - d]嘧啶 - 4 - 酮]的药理特性及其在体外和体内对缺血性损伤的神经保护作用。DR2313在体外竞争性抑制大鼠脑细胞核提取物中的聚（ADP - 核糖基）化（K(i)=0.23微摩尔）。在几种利用NAD(+)的酶中，DR2313对PARP具有特异性，但对PARP - 1和PARP - 2之间没有选择性。DR2313在水溶性和大鼠脑穿透性方面也表现出优异的特性。在脑缺血的体外模型中，暴露于过氧化氢或谷氨酸会因PARP过度激活而诱导细胞死亡，用DR2313处理可减少聚（ADP - 核糖）的过度形成和细胞死亡。在大鼠永久性和短暂性局灶性缺血模型中，用DR2313预处理（静脉推注10毫克/千克，静脉输注10毫克/千克/小时，持续6小时）可显著减少皮质梗死体积。为了确定DR2313神经保护的治疗时间窗，在短暂性局灶性缺血模型中检查了治疗后效应，并与自由基清除剂MCI - 186（3 - 甲基 - 1 - 苯基 - 2 - 吡唑啉 - 5 - 酮）的效应进行比较。用MCI - 186预处理（静脉推注3毫克/千克，静脉输注3毫克/千克/小时，持续6小时）可显著减少梗死体积，而治疗后则未显示任何效果。相比之下，在缺血后延迟2小时用DR2313（相同方案）进行治疗后仍可防止梗死进展。这些结果表明，即使在缺血后开始治疗，DR2313也可通过其有效的PARP抑制作用发挥神经保护作用。因此，像DR231这样的PARP抑制剂在治疗急性中风方面可能比自由基清除剂更有用。
