State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101, China.
Neurosci Lett. 2010 Mar 26;472(3):204-9. doi: 10.1016/j.neulet.2010.02.005. Epub 2010 Feb 10.
Although the relationship between hyperglycemia (using diabetic animal model) and plasma nitrotyrosine level has been studied, the effect of hypoglycemia on nitrotyrosine level in the brain has not been addressed. Here, we evaluated nitration of protein, the colocalization of nitration with alpha-synuclein, activity of inducible nitric oxide synthase, and nitric oxide content using fasting and diabetic animal models. The results showed that signals of alpha-synuclein were widely distributed in most parts of the pallium, midbrain, hippocampus and cerebellum, as indicated by immunohistochemistry. Most signals of the 3-nitrotyrosine were colocalized with those of alpha-synuclein in the midbrain of fasting rats. The level of proteins containing 3-nitrotyrosine was significantly increased in the brain of fasting rats in Western blotting, especially in the midbrain, compared with control rats. In addition, the 3-nitrotyrosine signals increased in hippocampus of diabetic rats. Immunoprecipitation showed that alpha-synuclein was nitrated in the fasting rats. The iNOS activity and nitric oxide levels were significantly increased in both fasting and diabetic animals. The enhanced 3-nitrotyrosine level in the brain of fasting rats suggests that nitration of protein including alpha-synuclein in the midbrain is more affected by hypoglycemia in fasting than hyperglycemia in diabetic rats.
虽然已经研究了高血糖（使用糖尿病动物模型）与血浆硝基酪氨酸水平之间的关系，但低血糖对大脑中硝基酪氨酸水平的影响尚未得到解决。在这里，我们使用禁食和糖尿病动物模型评估了蛋白质的硝化、硝化与α-突触核蛋白的共定位、诱导型一氧化氮合酶的活性和一氧化氮含量。结果表明，免疫组织化学染色显示，α-突触核蛋白的信号广泛分布于大脑皮层、中脑、海马和小脑的大部分区域。在禁食大鼠的中脑中，大多数 3-硝基酪氨酸信号与α-突触核蛋白的信号共定位。与对照组大鼠相比，Western blot 分析显示，禁食大鼠大脑中含有 3-硝基酪氨酸的蛋白质水平显著升高，尤其是在中脑中。此外，糖尿病大鼠的海马体中 3-硝基酪氨酸信号增加。免疫沉淀显示，α-突触核蛋白在禁食大鼠中发生硝化。在禁食和糖尿病动物中，iNOS 活性和一氧化氮水平均显著升高。禁食大鼠大脑中增强的 3-硝基酪氨酸水平表明，与糖尿病大鼠的高血糖相比，禁食时低血糖对中脑包括α-突触核蛋白在内的蛋白质硝化的影响更大。
