Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, Lawrence, Kansas 66045, USA.
Comp Biochem Physiol A Mol Integr Physiol. 2012 Apr;161(4):406-14. doi: 10.1016/j.cbpa.2011.12.014. Epub 2011 Dec 30.
The blind subterranean mole rat (Spalax ehrenbergi) exhibits a relatively long life span, which is attributed to an efficient antioxidant defense affording protection against accumulation of oxidative modifications of proteins. Methionine residues can be oxidized to methionine sulfoxide (MetO) and then enzymatically reduced by the methionine sulfoxide reductase (Msr) system. In the current study we have isolated the cDNA sequences of the Spalax Msr genes as well as 23 additional selenoproteins and monitored the activities of Msr enzymes in liver and brain of rat (Rattus norvegicus), Spalax galili, and Spalax judaei under normoxia, hypoxia, and hyperoxia. Under normoxia, the Msr activity was lower in S. galili in comparison to S. judaei and R. norvegicus especially in the brain. The pattern of Msr activity of the three species was similar throughout the tested conditions. However, exposure of the animals to hypoxia caused a significant enhancement of Msr activity, especially in S. galili. Hyperoxic exposure showed a highly significant induction of Msr activity compared with normoxic conditions for R. norvegicus and S. galili brain. It was concluded that among all species examined, S. galili appears to be more responsive to oxygen tension changes and that the Msr system is upregulated mainly by severe hypoxia.
盲地下鼹鼠（Spalax ehrenbergi）表现出相对较长的寿命，这归因于有效的抗氧化防御机制，能够防止蛋白质氧化修饰的积累。蛋氨酸残基可以被氧化为蛋氨酸亚砜（MetO），然后被蛋氨酸亚砜还原酶（Msr）系统酶促还原。在本研究中，我们分离了 Spalax Msr 基因的 cDNA 序列以及 23 种其他硒蛋白，并监测了正常氧、低氧和高氧条件下大鼠（Rattus norvegicus）、Spalax galili 和 Spalax judaei 的肝脏和大脑中 Msr 酶的活性。在正常氧条件下，S. galili 的 Msr 活性明显低于 S. judaei 和 R. norvegicus，尤其是在大脑中。在测试条件下，三种物种的 Msr 活性模式相似。然而，动物暴露于低氧会导致 Msr 活性显著增强，尤其是在 S. galili 中。与正常氧条件相比，高氧暴露会导致 R. norvegicus 和 S. galili 大脑中的 Msr 活性显著升高。结论是，在所检查的所有物种中，S. galili 似乎对氧张力变化更为敏感，而 Msr 系统主要通过严重的低氧而上调。
