Tissue protective effect of xanthine oxidase inhibitor, polymer conjugate of (styrene-maleic acid copolymer) and (4-amino-6-hydroxypyrazolo[3,4-d]pyrimidine), on hepatic ischemia-reperfusion injury
Tissue protective effect of xanthine oxidase inhibitor, polymer conjugate of (styrene-maleic acid copolymer) and (4-amino-6-hydroxypyrazolo[3,4-d]pyrimidine), on hepatic ischemia-reperfusion injury
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DOI：
10.1258/ebm.2009.009304
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发表时间：
2010-04-01
影响因子：
3.2
通讯作者：
Maeda, Hiroshi
中科院分区：
文献类型：
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作者：
Fang, Jun;Seki, Takahiro;Maeda, Hiroshi
超氧阴离子（O-2(-)）在缺血再灌注（I/R）损伤的发病机制中的有害作用已被充分证实。我们和其他研究表明，O-2（-）生成的一个关键来源可能是黄嘌呤氧化酶（XO）。因此，我们假设可以通过抑制XO活性来保护I/R损伤，从而减少O-2（-）的数量，从而减少致病后果。在各种XO抑制剂中，我们先前发现4-氨基-6-羟基吡唑[3,4-d]嘧啶（AHPP）具有有效的XO抑制活性。在此，我们报道了AHPP与两亲性苯乙烯-马来酸共聚物（SMA-AHPP）的共价偶联物对大鼠肝脏I/R模型中I/R诱导的损伤具有保护作用。阻断门静脉和肝动脉30min后再灌注肝缺血。SMA-AHPP在缺血开始前2小时通过尾静脉给药。再灌注3 h后血浆中肝酶（谷草转氨酶，AST，丙氨酸转氨酶，ALT，乳酸脱氢酶，LDH）显著升高，而事先注射SMA-AHPP可明显抑制AST， ALT， LDH的升高。此外，SMA-AHPP治疗可显著抑制I/R诱导的炎症细胞因子，即肿瘤坏死因子- α (tnf - α)、白细胞介素-12 （IL-12）和单核细胞趋化蛋白-1 （MCP-1）。因此，SMA-AHPP预处理明显降低了I/R引起的肝脏细胞毒作用或细胞凋亡。此外，硫代巴比妥酸反应物质测定显示，SMA-AHPP处理后大鼠肝脏脂质过氧化显著降低，这与SMA-AHPP处理后XO活性降低平行，表明XO产生的活性氧参与其中。此外，SMA-AHPP被发现与白蛋白结合，从而表现出较长的体内（血浆）半衰期。这些结果表明，SMA-AHPP通过抑制XO活性和O-2（-）的产生，对大鼠肝脏I/R损伤具有有效的细胞保护作用。
The detrimental role of superoxide anion (O-2(-)) has been well documented in the pathogenesis of ischemia-reperfusion (I/R) injury. Our and other studies suggested that one critical source of O-2(-) generation may be xanthine oxidase (XO). We thus hypothesized that I/R injury could be protected by inhibiting XO activity, which would reduce the amount of O-2(-) and hence reduce pathogenic consequences. Among various XO inhibitors, we previously found 4-amino-6-hydroxypyrazolo[3,4-d]pyrimidine (AHPP) exhibited potent XO inhibitory activity. Here, we report that the covalent conjugate of AHPP with amphipathic styrene-maleic acid copolymer (SMA-AHPP) showed protective effect against I/R-induced injury in a rat hepatic I/R model. Liver ischemia was induced by occluding both the portal vein and the hepatic artery for 30 min, and followed by reperfusion. SMA-AHPP was administered via the tail vein two hours before ischemia was initiated. A remarkable increase of liver enzymes in plasma (aspartate aminotransferase, AST; alanine aminotransferase, ALT and lactate dehydrogenase, LDH) was detected three hours after reperfusion, whereas prior injection of SMA-AHPP greatly suppressed this increase of AST, ALT and LDH. Moreover, induction of inflammatory cytokines, i.e. tumor necrosis factor-alpha (TNF-alpha), interleukin-12 (IL-12) and monocyte chemotactic protein-1 (MCP-1) by I/R were significantly inhibited by SMA-AHPP treatment. Accordingly, cytotoxic effect or apoptosis in the liver caused by I/R was clearly reduced by SMA-AHPP pretreatment. Furthermore, thiobarbituric acid-reactive substance assay showed a significant decrease of lipid peroxidation in rat liver after the administration of SMA-AHPP, which is parallel with the decreased XO activity after SMA-AHPP treatment, indicating the involvement of reactive oxygen species generated by XO. In addition, SMA-AHPP was found to bind to albumin, thus to exhibit prolonged in vivo (plasma) half-life. These results suggest that SMA-AHPP exerted a potent cytoprotective effect against I/R injury in rat liver, by inhibiting XO activity and the subsequent generation of O-2(-).