Division of Gastroenterology, Department of Internal Medicine, Cheng Hsin General Hospital, Taipei, Taiwan.
Int J Hyperthermia. 2012;28(5):421-30. doi: 10.3109/02656736.2012.677928. Epub 2012 Jun 12.
The present study was designed to elucidate the role of endothelial nitric oxide (NO) synthase (eNOS), inducible NOS (iNOS)-derived NO and heat-shock protein (Hsp70) in a rat model of whole-body hyperthermia (WBH)-induced liver injury.
Real-time polymerase chain reaction, immunohistochemistry and western blot were used to observe the mRNA and protein expression of eNOS, iNOS and Hsp70. Rats were exposed to hyperthermia by immersion for 60 min at a conscious state in a water bath maintained at 41°C. Plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were used to assess liver injury 15 h after the hyperthermia challenge. Nitrosative and oxidative mediators, particularly NO and hydroxyl radical were measured.
Plasma AST, ALT, hydroxyl radical, and NO were significantly increased after WBH. There were 4.14 ± 0.42, 2.82 ± 0.34 and 2.91 ± 0.16-fold increases in the mRNA expression of eNOS, iNOS and Hsp70. Immunohistochemistry and western blot showed up-regulation of eNOS, iNOS and Hsp70 protein. An eNOS inhibitor (N(ω)-nitro-L-arginine methyl ester (L-NAME)), or an iNOS inhibitor (aminoguanidine (AG)), significantly aggravated the liver injury. On the contrary, administration of NO precursor, L-arginine (L-ARG), attenuated the liver injury. Hsp70 inhibitor quercetin reduced Hsp70, while aggravating the WBH-induced hepatic changes.
WBH induces increases in eNOS, iNOS and Hsp70 expression with increase in NO release. The deleterious effects of L-NAME and AG and the protective effects of L-ARG and Hsp70 inhibitor on the liver function and pathology suggest that NO and heat shock protein play a beneficial role in the WBH-induced hepatic injury.
本研究旨在阐明内皮型一氧化氮合酶（eNOS）、诱导型一氧化氮合酶（iNOS）衍生的一氧化氮和热休克蛋白（Hsp70）在全身高热（WBH）诱导的肝损伤大鼠模型中的作用。
采用实时聚合酶链反应、免疫组织化学和蛋白质印迹法观察 eNOS、iNOS 和 Hsp70 的 mRNA 和蛋白表达。大鼠在 41°C 的水浴中清醒状态下浸泡 60 分钟以暴露于高温。在高温挑战后 15 小时，使用血浆天冬氨酸氨基转移酶（AST）和丙氨酸氨基转移酶（ALT）评估肝损伤。测量硝化和氧化介质，特别是一氧化氮和羟自由基。
WBH 后血浆 AST、ALT、羟自由基和一氧化氮显著增加。eNOS、iNOS 和 Hsp70 的 mRNA 表达分别增加了 4.14 ± 0.42、2.82 ± 0.34 和 2.91 ± 0.16 倍。免疫组织化学和蛋白质印迹显示 eNOS、iNOS 和 Hsp70 蛋白上调。eNOS 抑制剂（N（ω）-硝基-L-精氨酸甲酯（L-NAME））或 iNOS 抑制剂（氨基胍（AG））显著加重肝损伤。相反，给予一氧化氮前体 L-精氨酸（L-ARG）可减轻肝损伤。Hsp70 抑制剂槲皮素减少 Hsp70，同时加重 WBH 诱导的肝变化。
WBH 诱导 eNOS、iNOS 和 Hsp70 表达增加，导致一氧化氮释放增加。L-NAME 和 AG 的有害作用以及 L-ARG 和 Hsp70 抑制剂对肝功能和病理学的保护作用表明，一氧化氮和热休克蛋白在 WBH 诱导的肝损伤中发挥有益作用。
