青紫薯色素对^(60)Co辐射小鼠胸腺淋巴细胞的保护作用及其机制

PROTECTIVE EFFECTS OF ANTHOCYANIN FROM IPOMOEA BATATAS ON THYMOCYTES IRRADIATION DAMAGE CAUSED BY ^(60)Co γ-RAY IN MICE

①目的探讨青紫薯色素对60Coγ-射线单次辐射小鼠胸腺淋巴细胞辐射损伤的保护作用及其体外抗氧化作用机制。②方法建立60Co辐射(强度为3 Gy)对体外培养的小鼠胸腺淋巴细胞损伤病理模型,分为6组:对照组6、0Co模型组、0.625 g/L青紫薯色素组、1.250 g/L青紫薯色素组、2.500 g/L青紫薯色素组6、0Co+1 g/L Vit C组。琼脂糖凝胶电泳观察DNA Ladder;流式细胞仪PI染色测定细胞凋亡率;Fluo-3-AM荧光染色测定细胞内游离Ca2+浓度;免疫细胞化学法测定P53蛋白的表达;原位杂交检测细胞p21 mRNA的表达;化学发光法和电子自旋共振(ESR)捕集技术检测青紫薯色素对超氧阴离子(O2-)、羟自由基(OH.)、过氧化亚硝基(ONOO-)和脂类自由基的清除作用。③结果0.625~2.500 g/L浓度范围内青紫薯色素能抑制60Co辐射所致淋巴细胞DNA梯状带的出现,降低淋巴细胞凋亡率,降低淋巴细胞内游离Ca2+浓度,抑制60Co辐射后小鼠胸腺淋巴细胞P53蛋白在胞浆的表达,抑制60Co辐射后小鼠胸腺淋巴细胞p21 mRNA的表达,同时青紫薯色素还可有效清除O2-、OH.、ONOO-和脂类自由基。④结论青紫薯色素能抑制60Co辐射诱导的淋巴细胞凋亡,对60Co辐射损伤的小鼠胸腺淋巴细胞具有保护作用。其作用机制与青紫薯色素能清除氧自由基、降低细胞内游离Ca2+浓度、减少DNA的断裂、抑制突变型P53蛋白的表达、抑制p21基因的表达,影响淋巴细胞凋亡的信号转导中的基因调控有关。

Objective To study the protective effects of anthocyanin from Ipomoea batatas on thymocytes in Kunming mice damaged by ^60Co γ-ray（3 Gy）. Methods The irradiation damage models of thymocytes were established by ^60Co γ-ray. The cells were randomly divided into six groups： control group, and 5 ^60Co groups （model, 0. 625 g/L, 1. 250 g/L, 2. 500 g/L, anthocyanin from Ipomoea batatas,and 1 g/L Vit C）. The free calcium, mitochondria membrane potential and the rate of apoptosls of thymocytes were tested using flow cytometry （FCM）. The expressions of P53 proteins were examined immunocytochemically. The p21 expression was determined with in situ hybridization. The scavenging properties of anthocyanin from Ipomoea batatas on superoxide anions （O2^-）, hydroxyl radical （OH^＋）, peroxynitrite （ONOO^-） and free radicals of lipids were determined with chemiluminescence and electron spin resonance （ESR） techniques. Results The concentration of cellular free calcium was decreased by Ipomoea batatas Poir. Ipomoea batatas Poir decreased the rate of apoptosis and the expression of P53. The mRNA expressions of p21 decreased in Ipomoea batatas Poir group. The anthocyanin from Ipomoea batatas could effectively scavenge O2^- , OH^＋ , ONOO^- and free radicals of lipids. Conclusion Ipomoea batatas Poir has protective effects on damages of thymocytes caused by the ^60Co irradiation, whose mechanism might be related to the inhibition of free radicals, cellular free calcium and decreased expression of P53 and p21 gene, increased anti-oxidative enzymes in cells and inhibition of the lipid peroxide.