Zhang Wenyi, Niu Cuijuan, Liu Yukun, Chen Bojian
Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing 100875, China.
Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing 100875, China.
Comp Biochem Physiol B Biochem Mol Biol. 2017 May;207:9-14. doi: 10.1016/j.cbpb.2017.02.003. Epub 2017 Feb 13.
Glutathione (GSH) system is a critical component of antioxidant defense, which is important for hibernating survive of turtle hatchlings. The present work measured changes at the mRNA level of genes involved in GSH synthesis, GSH reduction and GSH utilization, as well as enzyme activity, in Pelodiscus sinensis hatchlings during hibernation. Samples were taken in the field at pre-hibernation (17°C, Mud temperature (MT)), hibernation (5.8°C, MT) and arousal (20.1°C, MT). Cerebral total GSH content decreased during hibernation, recovered after arousal along with a stable ratio of GSH/GSSG. Hepatic total GSH increased after arousal and pushed the ratio of GSH/GSSG to a more reduced status. Cerebral glutathione reductase (GR) mRNA and activity were depressed during hibernation then recovered after arousal. However, hepatic GR mRNA elevated during hibernation but its activity did not change. Tissue-specific changes of GR activity and mRNA may promote these tissue-specific changes of GSH redox. Hibernation caused little effect on mRNA level of glutathione synthetase (GS) while arousal induced them in the brain and liver. Most Glutathione-S-transferase (GST) isoform mRNAs did not change in both brain and liver during hibernation, then induced after arousal. Cerebral and hepatic GST activities kept stable throughout the entire experiment. Our results showed that GSH system may play a more important role in antioxidant defense in the liver while mainly maintaining stable redox balance in the brain of hibernating P. sinensis hatchings.
谷胱甘肽（GSH）系统是抗氧化防御的关键组成部分，对中华鳖幼体的冬眠存活至关重要。本研究测定了中华鳖幼体在冬眠期间参与GSH合成、GSH还原和GSH利用的基因的mRNA水平变化以及酶活性。在冬眠前（17°C，泥温（MT））、冬眠期（5.8°C，MT）和苏醒期（20.1°C，MT）在野外采集样本。冬眠期间脑内总GSH含量下降，苏醒后恢复，同时GSH/GSSG比值保持稳定。苏醒后肝脏总GSH增加，并使GSH/GSSG比值降至更低水平。冬眠期间脑内谷胱甘肽还原酶（GR）mRNA和活性降低，苏醒后恢复。然而，肝脏GR mRNA在冬眠期间升高但其活性未改变。GR活性和mRNA的组织特异性变化可能促进了GSH氧化还原的这些组织特异性变化。冬眠对谷胱甘肽合成酶（GS）的mRNA水平影响较小，而苏醒则在脑和肝脏中诱导其表达。大多数谷胱甘肽-S-转移酶（GST）同工型mRNA在冬眠期间脑和肝脏中均未改变，苏醒后诱导表达。在整个实验过程中，脑和肝脏的GST活性保持稳定。我们的结果表明，GSH系统可能在肝脏的抗氧化防御中发挥更重要的作用，而在中华鳖冬眠幼体的脑中主要维持稳定的氧化还原平衡。
