Veterinary Technology Program, Faculty of Technology, Udon Thani Rajabhat University, Udon Thani, 41000, Thailand.
Department of Pharmacology, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand.
Phytother Res. 2016 Feb;30(2):227-33. doi: 10.1002/ptr.5520. Epub 2015 Nov 17.
Oxidative stress has been shown to play an important role in development of vascular dysfunction in diabetes. Protocatechuic acid (PCA) has been reported to exert antioxidant and anti-hyperglycemic activities. Diabetes was induced in male Sprague-Dawley rats by a single intraperitoneal injection of 50 mg/kg streptozotocin (STZ). The rats were maintained in a state of hyperglycemia for 12 weeks. Then, PCA (50 or 100 mg/kg/day) was administered orally or insulin (4 U/kg/day) was subcutaneous injected to the rats for 6 weeks. Blood pressure, vascular responses to vasoactive agents, vascular superoxide production, blood glucose, insulin, malondialdehyde, nitric oxide and antioxidant enzymes were examined. The diabetic rats showed weight loss, insulin deficiency, hyperglycemia, increased oxidative stress, decreased plasma nitric oxide, elevated blood pressure, increased vascular response to phenylephrine and decreased vascular responses to acetylcholine and sodium nitroprusside. PCA significantly decreased blood glucose and oxidative stress, and increased plasma nitric oxide in diabetic rats. Interestingly, PCA treatment restored blood pressure and vascular reactivity, and antioxidant enzyme activity diabetic rats. This study provides the first evidence of the efficacy of PCA in restoring the vascular reactivity of diabetic rats. The mechanism of action may be associated with an alleviation of oxidative stress.
氧化应激在糖尿病血管功能障碍的发展中起着重要作用。原儿茶酸（PCA）已被报道具有抗氧化和抗高血糖作用。雄性 Sprague-Dawley 大鼠通过单次腹腔注射 50mg/kg 链脲佐菌素（STZ）诱导糖尿病。大鼠维持高血糖状态 12 周。然后，PCA（50 或 100mg/kg/天）口服给药或胰岛素（4U/kg/天）皮下注射给药 6 周。检查血压、血管对血管活性物质的反应、血管超氧化物产生、血糖、胰岛素、丙二醛、一氧化氮和抗氧化酶。糖尿病大鼠表现出体重减轻、胰岛素缺乏、高血糖、氧化应激增加、血浆一氧化氮减少、血压升高、对苯肾上腺素的血管反应增加和对乙酰胆碱和硝普钠的血管反应减少。PCA 可显著降低糖尿病大鼠的血糖和氧化应激，并增加血浆一氧化氮。有趣的是，PCA 治疗可恢复糖尿病大鼠的血压和血管反应性以及抗氧化酶活性。本研究首次提供了 PCA 恢复糖尿病大鼠血管反应性的疗效证据。其作用机制可能与减轻氧化应激有关。
