Expression of arginyl-tRNA synthetase in rats with focal cerebral ischemia.

Aminoacyl-tRNA syntheses (AARS) can catalyze the adenosine triphosphate (ATP)-dependent acylation of their cognate tRNA(s) with a specific amino acid. They can be seen as an index to reflect the energy metabolic rate of ischemic brain cells in ischemic penumbra. This study examined the relationship between arginyl-tRNA synthetase (ArgRS), one of the AARS, and cerebral ischemia in rats. The model of middle cerebral artery occlusion (MCAO) was established in rats. The expression levels of ArgRS protein and mRNA were detected in rat brain tissues at different time points following MCAO by Western blotting and RT-PCR, respectively. The results showed that the MCAO model was successfully established. Western blotting and RT-PCR analysis revealed that the ArgRS protein and mRNA were expressed in brain cells in both ischemic and normal penumbra tissues. The expression levels of ArgRS protein and mRNA peaked at 6 h after MCAO and decreased gradually. At 24 h, the expression levels of ArgRs protein and mRNA in ischemic penumbral tissues were lower than those in normal tissues. The expression levels of ArgRS mRNA and protein in ischemic penumbra varied with ischemic time, suggesting that the energy metabolism of brain cells in penumbra changed dynamically after ischemia to ensure the endogenous self-protection of the body. The brain oxygen supply should be improved as soon as possible, especially within 6-12 h after ischemia, so as to meet the demand for energy metabolism in ischemic penumbra and make sure the cell structure remains stable.