Niu Chiang-Shan, Chen Li-Jen, Niu Ho-Shan
Department of Nursing, Tzu Chi College of Technology, Hualien City 97005, Taiwan.
BMC Complement Altern Med. 2014 Jan 13;14:20. doi: 10.1186/1472-6882-14-20.
Rhodiola rosea (Rhodiola) is a plant in the Crassulaceae family that grows in cold regions of the world. It is mainly used in clinics as an adaptogen. Recently, it has been mentioned that Rhodiola increases plasma β-endorphin to lower blood pressure. Thus, the present study aims to investigate the antidiabetic action of Rhodiola in relation to opioids in streptozotocin-induced diabetic rats (STZ-diabetic rats).
In the present study, the plasma glucose was analyzed with glucose oxidase method, and the determination of plasma β-endorphin was carried out using a commercially available enzyme-linked immunosorbent assay. The adrenalectomy of STZ-diabetic rats was used to evaluate the role of β-endorphin. In addition, quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and western blotting analysis were performed to investigate mRNA and protein expressions.
Rhodiola-water extract dose-dependently lowered the plasma glucose in STZ-diabetic rats and this action was reversed by blockade of opioid μ-receptors using cyprodime. An increase of plasma β-endorphin by rhodiola-water extract was also observed in same manner. The plasma glucose lowering action of rhodiola-water extract was attenuated in bilateral adrenalectomized rats. In addition, continuous administration of rhodiola-water extract for 3 days in STZ-diabetic rats resulted in an increased expression of glucose transporter subtype 4 (GLUT 4) in skeletal muscle and a marked reduction of phosphoenolpyruvate carboxykinase (PEPCK) expression in liver. These effects were also reversed by blockade of opioid μ-receptors.
Taken together, rhodiola-water extract improves hyperglycemia via an increase of β-endorphin secretion from adrenal gland to activate opioid μ-receptors in STZ-diabetic rats.
红景天是景天科植物，生长于世界寒冷地区。临床上主要用作适应原。最近，有人提到红景天可增加血浆β-内啡肽以降低血压。因此，本研究旨在探讨红景天在链脲佐菌素诱导的糖尿病大鼠（STZ糖尿病大鼠）中与阿片类物质相关的抗糖尿病作用。
在本研究中，采用葡萄糖氧化酶法分析血浆葡萄糖，并使用市售酶联免疫吸附测定法测定血浆β-内啡肽。采用STZ糖尿病大鼠肾上腺切除术评估β-内啡肽的作用。此外，进行定量逆转录-聚合酶链反应（qRT-PCR）和蛋白质印迹分析以研究mRNA和蛋白质表达。
红景天水提取物剂量依赖性地降低STZ糖尿病大鼠的血浆葡萄糖，并且使用环丙胺阻断阿片类μ受体可逆转此作用。以相同方式也观察到红景天水提取物使血浆β-内啡肽增加。红景天水提取物降低血浆葡萄糖的作用在双侧肾上腺切除的大鼠中减弱。此外，在STZ糖尿病大鼠中连续3天给予红景天水提取物导致骨骼肌中葡萄糖转运蛋白4（GLUT 4）表达增加，肝脏中磷酸烯醇丙酮酸羧激酶（PEPCK）表达明显降低。这些作用也通过阻断阿片类μ受体而逆转。
综上所述，红景天水提取物通过增加肾上腺β-内啡肽分泌以激活STZ糖尿病大鼠的阿片类μ受体来改善高血糖。
