锌源及锌水平对体外培养胸腺细胞凋亡的影响及其机制  

Effects and Mechanism of Zinc Sources and Chelation Levels on Apoptosis of Thymocytes Cultured in Vitro

作　　者：虞泽鹏 施用晖 黄红宇[2] 魏云玉[2] 乐国伟 李吕木 

机构地区：[1]江南大学营养与生物技术教研室,江苏无锡214036 [2]无锡市第二人民医院中心实验室,江苏无锡214000

出　　处：《食品科学》2005年第2期202-207,共6页Food Science

基　　金：科技部农业成果转化项目(2002730020773)

摘　　要：目的:研究不同锌补加形式和补加水平对体外培养胸腺细胞凋亡的影响及其机制。方法:采用地塞米松作为诱导剂,建立小鼠胸腺细胞体外培养的凋亡模型,培养基中分别补加0、50、100、500、1000μmol/L的硫酸锌或蛋氨酸锌,培养16h。测定细胞凋亡率、细胞内钙离子浓度、DNA片段化等指标。结果:添加硫酸锌与蛋氨酸锌对体外地塞米松诱导的小鼠胸腺凋亡均有抑制作用。不同浓度的锌均能在一定程度上抑制凋亡的发生,减少DNA片段化,且这种抑制作用具有剂量效应。50～100μmol/L添加水平时,蛋氨酸锌对细胞凋亡的抑制作用低于硫酸锌(p<0.05),但蛋氨酸锌处理组细胞内钙离子浓度显著高于硫酸锌处理组(p<0.05)。500～1000μmol/L时,两种锌对凋亡抑制作用相近(p>0.05),蛋氨酸锌处理组细胞内钙浓度明显高于硫酸锌处理(p<0.05)。锌水平增加显著降低细胞内钙离子浓度(p<0.05);锌补加水平升高时,胞内Cu、Zn-SOD活性随之增高,细胞培养上清液中AKP活性也有上升趋势。结论:两种锌源均能抑制地塞米松体外诱导的胸腺细胞凋亡,其机制可能涉及到细胞内Ca2+浓度、细胞内氧化还原状态的变化等生理生化过程。Object: To investigate the effects of different zinc sources and levels of addifion on apoptosis and their mechanism. Method: Dexamethasone was used to make the apoptosis model of thymocytes. Zinc sulfate and zinc methionine were added to the medium with the levels of 0, 50, 100, 500, 1000μmol/L. The activity AKP, Cu, Zn-SOD and intracellular calcium concentration and the percentage of apoptosis nuclei were determined. Result: Both ZnSO4 and Zn-Met could modulate apoptosis. They inhibited apoptosis and decreased DNA ladder formation; and the modulation would rely on the dose of zinc. Supple- mented with 50, 100μmol/L zinc, the ability of Zn-Met inhibiting apoptosis was less efficiency than ZnSO4 (p<0.05), and of no difference to modulate apoptosis when being added with 500 or 1000μmol/L to the medium (p>0.05). Intracellular calcium concentrations of cells cultured with Zn-Met were higher than those cultured with ZnSO4 of the same level. Zinc supplementation decreased the concentration of intracellular calcium significantly (p<0.05), but increased the activity of Cu, Zn-SOD (p<0. 05) in the extract of the cells, and AKP in the supernatant of the culture fluids (p>0.05). Conclusion: Both forms of zinc could modulate apoptosis of thymocytes induced by glucocorticoid. The mechanism might involve the exchange of intracellular calcium and the redox of cells.

关 键 词：硫酸锌 蛋氨酸锌 凋亡 体外培养 地塞米松 胸腺细胞 

分 类 号：Q945.12[生物学—植物学]