中文摘要：

目的：本研究旨在明确羟基磷灰石纳米粒子（HAP）在体外能否诱导人结肠癌SW-480细胞凋亡并从凋亡角度探讨其抑癌机制。方法：用HAP以不同浓度作用于人结肠癌SW-480细胞，以诱导其凋亡。用MTT比色法观察其细胞毒性，荧光显微镜、透射电镜、琼脂糖凝胶电泳法及流式细胞术（FCM）等方法来检测凋亡，观察其形态学和生化方面的变化。结果：HAP以剂量和时间依赖的方式抑制人结肠癌SW-480细胞的生长。25mg／L，50mg／L HAP作用72h细胞的生长抑制率分别是49．71％和61．03％。12．5-100mg／L的HAP处理48h后，结肠癌细胞表现为细胞皱缩、核质浓缩、核碎裂、细胞起泡以及凋亡小体形式等凋亡特征的形态学改变。流式细胞仪均能检测到凋亡峰，12．5，25，50，100mg／L HAP作用48h，凋亡率分别是3．57％，21．45％，37．10％和49．45％。结论：HAP在体外能抑制人结肠癌SW-480细胞增殖并诱导细胞凋亡。

英文摘要：

Objective： To investigate whether apoptosis can be induce by hydroxyapatite nanoparticles （HAP） in human colon carcinoma cell line SW-480 in vitro. Methods： The selected human colon carcinoma cell line SW-480 was treated with HAP at various concentrations. Growth suppression and apoptosis-related alterations were evaluated by MTT method, cytochemical staining （Hoechst 33258）, transmission electron microscopy, DNA agarose gel eletrophoresis and flow cytometry （FCM）. Results： HAP inhibited the growth of colon carcinoma cells in a dose and time-dependent manner. HAP displayed prominent inhibitory effects at 25 and 50 mg/L at 72 hours, and the growth inhibition rates of cancer cells reached 49.71% and 61.03%. With 12.5-100 mg/L HAP for 48 h, apoptosis along with nuclear chromatin condensation and fragmentation as well as cell shrinkage and the formation of apoptotic bodies was observed using fluorescent microscope and transmission electron microscopy. Flow cytometry analysis showed hypodiploid peaks on histogram, the apoptotic rates at concentrations of 12.5,25,50 and 100 mg/L were 2.7%, 12.5%, 23.6% and 37.1% respectively at 48 hours. Conclusion： HAP not only inhibited proliferation but also induced apoptosis of human colon carcinoma cell line sw-480, which may be related to the mechanism of antineoplastic action of HAP in colon carcinoma.