Liposome-encapsulated glycyrrhizin alleviates hyperglycemia and glycation-induced iron-catalyzed oxidative reactions in streptozotocin-induced diabetic rats

Glycyrrhizin, a bioactive constituent of Glycyrrhiza glabra has been reported to ameliorate diabetes. Here, the effects of liposome-encapsulated glycyrrhizin on STZ-induced diabetes and associated oxidative stress were investigated. Wistar rats were grouped as control (NC, received placebo), diabetic (DC, STZ-induced), diabetic treated with free glycyrrhizin (DTG, 3 i.v. doses, 1.6 mg/0.5 ml), empty liposomes (DTl, 3 i.v. doses), and liposome-encapsulated glycyrrhizin (DTbd, 3 i.v. doses, 1.6 mg/0.5 ml). Serum glucose, insulin, intraperitoneal glucose tolerance test and glycohemoglobin were estimated. Free iron and iron-mediated oxidative stress were examined. Histological examinations of the kidney and liver were performed. Liposomal-glycyrrhizin treatment caused significant improvement of hyperglycemia (DC vs. DTbd p p p p p p p p p 2O2 vs. DTbd + H2O2 p 2O2 vs. DTbd + H2O2, p甘草酸（Glycyrrhizin）是光果甘草（Glycyrrhiza glabra）的生物活性组分，已有研究表明其可改善糖尿病病症。本研究探讨了脂质体包封甘草酸（liposome-encapsulated glycyrrhizin）对链脲佐菌素（STZ）诱导的糖尿病及相关氧化应激的影响。实验将Wistar大鼠分为五组：正常对照组（NC，给予安慰剂）、糖尿病模型组（DC，经STZ诱导造模）、游离甘草酸治疗组（DTG，静脉注射3次，每次剂量1.6 mg/0.5 ml）、空白脂质体组（DTl，静脉注射3次）以及脂质体包封甘草酸治疗组（DTbd，静脉注射3次，每次剂量1.6 mg/0.5 ml）。随后检测各组大鼠的血清葡萄糖、胰岛素水平、腹腔葡萄糖耐量试验（intraperitoneal glucose tolerance test）结果及糖化血红蛋白（glycohemoglobin）水平；检测游离铁及铁介导的氧化应激指标；并对肾脏与肝脏组织开展组织病理学检查。脂质体包封甘草酸治疗可显著改善高血糖状态（DC组与DTbd组比较，显著性标记为p p p p p p p p p；另有过氧化氢（H₂O₂）与DTbd + H₂O₂组的比较：p 2O2 vs. DTbd + H2O2，p 2O2 vs. DTbd + H2O2，p）。