Comparison of Ascorbic Acid Levels and Hepatic L-Gulonolactone Oxidase Activity in KK-Ay Mice and Streptozotocin-Diabetic Mice under Hyperglycemic Conditions.

IF 0.7 4区 医学 Q4 NUTRITION & DIETETICS
Keizo Umegaki, Kaori Yokotani, Kanna Ieiri, Hiroaki Kawasaki
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Abstract

Blood ascorbic acid (AsA) concentrations are lower in diabetic patients than in the general population, a phenomenon that is also observed in streptozotocin (STZ)-diabetic models of type 1 diabetes. However, the occurrence of diabetes in KK-Ay mice, a model for type 2 diabetes, the most common form of diabetes, remains unclear. Although this mouse can synthesize AsA, understanding its level changes during diabetes progression could help in analyzing AsA's effects on type 2 diabetes. Therefore, the present study investigated the relationship between hyperglycemia and AsA concentrations in the blood and organs of KK-Ay mice, and discussed the findings in relation to those observed in STZ-diabetic mice. Male KK-Ay mice were examined at different stages of diabetes (pre-diabetic, early onset, and hyperglycemic maintenance). STZ-diabetic mice were generated by administering STZ to ICR mice. AsA concentrations were measured in plasma, blood mononuclear cells, and tissues, along with hepatic L-gulonolactone oxidase (GLO) activity and mRNA expression levels. Unexpectedly, AsA concentrations in KK-Ay mice increased under hyperglycemic conditions, while they decreased in STZ-diabetic mice. A consistent relationship was not observed between organ AsA concentrations and hyperglycemia. GLO activity and mRNA expression levels increased in KK-Ay mice, but decreased in STZ-diabetic mice, suggesting an innate defense mechanism against hyperglycemia in KK-Ay mice. These results indicate that different diabetes models exhibit distinct changes in AsA concentrations and hepatic GLO activity under hyperglycemic conditions, highlighting the importance of considering endogenous AsA when evaluating the antioxidant properties of dietary components in KK-Ay mice.

高血糖条件下KK-Ay小鼠和链脲霉素糖尿病小鼠抗坏血酸水平和肝脏l -古罗内酯氧化酶活性的比较
糖尿病患者血液中抗坏血酸(AsA)浓度低于一般人群,这一现象在1型糖尿病的链脲佐菌素(STZ)-糖尿病模型中也观察到。然而,糖尿病在KK-Ay小鼠(2型糖尿病的模型,最常见的糖尿病形式)中的发生尚不清楚。虽然该小鼠可以合成AsA,但了解其在糖尿病进展过程中的水平变化有助于分析AsA对2型糖尿病的影响。因此,本研究探讨了KK-Ay小鼠血液和器官中AsA浓度与高血糖的关系,并讨论了与stz -糖尿病小鼠相关的结果。雄性KK-Ay小鼠在糖尿病的不同阶段(糖尿病前期、早期发病和高血糖维持)进行了检查。通过给ICR小鼠注射STZ产生STZ糖尿病小鼠。测定血浆、血单个核细胞和组织中AsA浓度,以及肝脏l -谷洛内酯氧化酶(GLO)活性和mRNA表达水平。出乎意料的是,KK-Ay小鼠的AsA浓度在高血糖状态下升高,而stz -糖尿病小鼠的AsA浓度则下降。没有观察到器官AsA浓度与高血糖之间的一致关系。GLO活性和mRNA表达水平在KK-Ay小鼠中升高,而在stz -糖尿病小鼠中降低,提示KK-Ay小鼠对高血糖存在先天防御机制。这些结果表明,不同的糖尿病模型在高血糖条件下表现出不同的AsA浓度和肝脏GLO活性变化,突出了在评估KK-Ay小鼠饮食成分的抗氧化性能时考虑内源性AsA的重要性。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
CiteScore
1.80
自引率
6.20%
发文量
63
审稿时长
6-12 weeks
期刊介绍: The Journal of Nutritional Science and Vitaminology is an international medium publishing in English of original work in all branches of nutritional science, food science and vitaminology from any country. Manuscripts submitted for publication should be as concise as possible and must be based on the results of original research or of original interpretation of existing knowledge not previously published. Although data may have been reported, in part, in preliminary or abstract form, a full report of such research is unacceptable if it has been or will be submitted for consideration by another journal.
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