Sridulyakul Pattarin, Wongeak-In Natchaya, Patumraj Suthiluk
Department of Biology, Faculty of Science, Srinakharinwirot University, Bangkok 10110, Thailand.
Int J Vasc Med. 2012;2012:709695. doi: 10.1155/2012/709695. Epub 2012 May 28.
The correlation between endothelial function and reactive oxygen species detecting from diabetic microvascular wall and the antioxidant effect of ascorbic acid (AA) during early and late phases of diabetic induction were determined. Male Spraque-Dawley rats were divided into four groups: control, diabetes rats (DM, using iv.injection of 55 mg/kg BW streptozotocin, (STZ)), and two groups of DM rats treated with AA (1 g/L, (STZ)) starting on day 2 (DM + AAday2) and week 6th (DM + AA6wk). On 12th week after STZ injection, the findings showed that in DM group, Ach (10(-5) M)-induced vasodilatation was decreased, while the number of leukocyte adhesion was increased significantly (P < 0.01). Interestingly, these abnormalities induced by DM could be protected or improved in both AA-treated groups, DM + AAday2 and DM + AA6wk. By using dihydrorhodamine 123, our findings also indicated that the existing of ROS productions on diabetic arteriolar and venular walls were different significantly (ROS(arteriole) = 165.89 ± 24.59 and ROS(venule) = 172.26 ± 34.70) (P < 0.05). Moreover by using BH4 inhibitor to induce increase in arteriolar ROS, the results also confirmed that AA could improve endothelial function with closed correlation to its potential to reduce vascular ROS content.
测定糖尿病微血管壁内皮功能与活性氧之间的相关性，以及糖尿病诱导早期和晚期抗坏血酸（AA）的抗氧化作用。雄性Sprague-Dawley大鼠分为四组：对照组、糖尿病大鼠（DM，静脉注射55mg/kg体重链脲佐菌素（STZ）），以及两组从第2天（DM + AAday2）和第6周（DM + AA6wk）开始用AA（1g/L，STZ）治疗的糖尿病大鼠。在注射STZ后第12周，结果显示，在DM组中，乙酰胆碱（10(-5)M）诱导的血管舒张降低，而白细胞黏附数量显著增加（P < 0.01）。有趣的是，DM诱导的这些异常在两个AA治疗组DM + AAday2和DM + AA6wk中均可得到保护或改善。通过使用二氢罗丹明123，我们的研究结果还表明，糖尿病小动脉和小静脉壁上活性氧的产生存在显著差异（ROS(小动脉)= 165.89 ± 24.59和ROS(小静脉)= 172.26 ± 34.70）（P < 0.05）。此外，通过使用四氢生物蝶呤抑制剂诱导小动脉活性氧增加，结果还证实AA可改善内皮功能，且与其降低血管活性氧含量的潜力密切相关。
