Mechanism of Renal Injury by Active Oxygen Species Produced by Cytochrome P450

细胞色素P450产生的活性氧损伤肾的机制

• 批准号: 08670185
• 负责人: IMAOKA Susumu
• 金额: $ 1.41万
• 依托单位: Osaka city University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08670185/
• 关键词: cytochrome P450; active oxygen; free radical; renal iniury

Diabetes, ischemia/reperfusion, and some drus such as cyclosporin induce renal failure. Free radicals are thought to be an important factor in renal injury but its mechanism is not clear. Cytochrome P450 (P450) which is a monooxygenase produces active oxygen species. It is reported that an inhibitor of P450 reduces renal injury caused by ischemia/reperfusion. In this study, a role of free radical produced by P450 in renal injury was investigated. First, isoforms of P450 which produced hydroxyl radicals were identified by electron spin resonance (ESR). CYP2B1 and 3A2 had the highest activity for hydroxyl radical production and CYP2E1 and 4A2 had the next highest activity. CYP2B1 and 3A2 are phenobarbital (PB)-inducible forms in rat liver. CYP2E1 is induced in live and kidney by alcohol and diabetes. CYP4A2 is a major renal P450 and induced by cyclosporin. Treatment of rats with PB induced lipid-peroxidation and increased 8-hydroxy-2'-deoxyguanosine (8-OHdG), DNA damage maker, in rat liver. In addition, immunochemical study with antibodies against CYP2B1 and 8-OHdG revealed that areas stained with CYP2B1 antibody were identical with those with 8-OHdG antibody. Furthermore, LLC-PK1 cells which derived from kidney was used for ischemia/reperfusion model. Cell damage was assayd by release of lactate dehydrogenase (LDH). An inhibitor for electron transfer system constituted with NADPH, P450-reductase, and P450 decreased the release of LDH,indicating that the inhibitor decreased the cell damage caused by active oxygen species.These findings suggested that active oxygen species produced by P450 damaged membrane lipids and reached genomic DNA.P450 has an important role in renal injury caused by free radicals.

糖尿病、缺血/再灌注和某些药物如环孢菌素可引起肾衰竭。自由基被认为是肾损伤的重要因素，但其机制尚不清楚。细胞色素P450（P450）是一种产生活性氧的单加氧酶。据报道，P450的抑制剂减少由缺血/再灌注引起的肾损伤。在这项研究中，P450产生的自由基在肾损伤中的作用进行了研究。首先，通过电子自旋共振（ESR）鉴定产生羟基自由基的P450亚型。CYP 2B 1和3A 2具有最高的羟基自由基产生活性，CYP 2 E1和4A 2具有次高活性。CYP 2B 1和3A 2在大鼠肝脏中是苯巴比妥（PB）可诱导的形式。CYP 2 E1在肝脏和肾脏中被酒精和糖尿病诱导。CYP 4A 2是一种主要的肾脏P450，由环孢菌素诱导。PB处理可引起大鼠肝脏脂质过氧化和DNA损伤标志物8-羟基脱氧鸟苷（8-OHdG）的增加。此外，用抗CYP 2B 1和8-OHdG抗体的免疫化学研究显示，CYP 2B 1抗体染色的区域与8-OHdG抗体染色的区域相同。此外，来源于肾脏的LLC-PK 1细胞用于缺血/再灌注模型。以乳酸脱氢酶（LDH）释放量测定细胞损伤程度。由NADPH、P450-还原酶和P450组成的电子传递系统抑制剂可以减少LDH的释放，表明该抑制剂可以减轻活性氧自由基对细胞的损伤。这些结果表明，P450产生的活性氧自由基破坏膜脂质并到达基因组DNA。P450在自由基引起的肾脏损伤中发挥重要作用。

项目成果

Kunitoh, S., Imaoka, S., Hiroi, T., Yabusaki, Y., Monna, T., and Funae, Y.: "Acetaldehyde as well as ethanol is metabolized by human CYP2E1." J.Pharmacol.Exp.Ther.280. 527-532 (1997)

Kunitoh, S.、Imaoka, S.、Hiroi, T.、Yabusaki, Y.、Monna, T. 和 Funae, Y.：“乙醛和乙醇由人类 CYP2E1 代谢。”

Minamiyama, Y., Takemura, S., Imaoka, S., Funae, Y.et al.: "Irreversible inhibition of cytochrome P450 by nitric oxide." J.Pharmacol.Exp.Ther.283. 1479-1485 (1997)

Minamiyama, Y.、Takemura, S.、Imaoka, S.、Funae, Y.等人：“一氧化氮对细胞色素 P450 的不可逆抑制。”

Kunitoh, S., Imaoka, S.Hiroi, T.Yabusaki, Y., Monna, T.et al.: "Acetaldehyde as well as ethanol is metabolized by human CYP2E1." J.Pharmacol.Exp.Ther.280. 527-532 (1997)

Kunitoh, S.、Imaoka, S.Hiroi、T.Yabusaki, Y.、Monna, T.等人：“乙醛和乙醇均由人类 CYP2E1 代谢。”

Nakamura, M., Imaoka, S., Tanaka, E., Misawa, S., and Funae, Y.: "Cis-diamminedichloroplatinum induces peroxisomes as well as CYP4A1 in rat kidney." Res.Commun.Mol.pathol. Pharmacol.(in press).

Nakamura, M.、Imaoka, S.、Tanaka, E.、Misawa, S. 和 Funae, Y.：“顺式二氯二氨铂在大鼠肾脏中诱导过氧化物酶体以及 CYP4A1。”

Tamura, Y., Imaoka, S., Gemba, M., Funae, Y.: "Effects of ischemia-reperfusion on individual cytochrome P450 isoforms in the rat kidney." Life Sci.60. 143-149 (1997)

Tamura, Y.、Imaoka, S.、Gemba, M.、Funae, Y.：“缺血再灌注对大鼠肾脏中单个细胞色素 P450 同工型的影响。”