核素凋亡显像评价小鼠肝细胞凋亡

目的将凋亡显像剂99mTc-HYNIC-Annexin V用于肝细胞凋亡小鼠动物模型显像,以评价其用于显示凋亡的可行性。方法通过双功能螯合剂HYNIC偶联Annexin V后99mTc标记,鉴定99mTc-HYNIC-Annexin V标记率、放化纯和稳定性。取正常昆明小鼠随机分为正常对照组及应用anti-Fas抗体处理后肝细胞凋亡组,注射显像剂后不同时间行SPECT显像,考察显像剂在小鼠体内分布及排泄情况,应用感兴趣区(region of interest,ROI)技术比较正常组及凋亡组显像图像中肝脏/前臂比值。取两组动物肝脏组织HE染色进行病理学分析,Hoechst33258染色检测凋亡。结果99mTc-HYNIC-Annexin V标记率可达(96.32±2.08)%,放化纯度达到(96.90±2.27)%,标记物体外稳定。正常小鼠体内显像剂从肾脏排泄,肝脏仅有少量分布。凋亡组肝脏有明显显像剂浓聚,不同时间下肝脏/前臂的比值均高于正常小鼠。HE染色及Hoechst33258染色提示凋亡组有大量肝细胞凋亡。结论研究制备的凋亡显像剂99mTc-HYNIC-Annexin V可以活体显示发生凋亡的肝脏,用于在体凋亡显像,有望成为一种有良好临床应用前景的凋亡显像剂。

Radionuclide apoptosis imaging on hepatocyte apoptosis of mice models

Objective To assess the value of ^99mTc-HYNIC-Annexin V as apoptosis imaging agent in hepatocytes apoptosis of mice models. Methods The expression plasmid of human Annexin V was constructed and expressed. HYNIC was used as bifunctional chelating agent for ^99mTc labeling Annexin V. The radiochemical purity, radiolabeling yield and stability of ^99mTc-HYNIC-Annexin V were studied. Normal Kunming mice were randomly divided into normal control group and hepatocytes apoptosis group after treated by saline and anti-Fas antibody, respectively. SPECT images in different time were obtained to evaluate the biodistribution of the agent in the two groups. The ratios of liver/upper-limb were gained with region of interest (ROI) technique and compared between the two groups. Livers in both groups were used to HE and Hoechst 33258 staining for checking of apoptosis. Results Annexin V could be labeled with ^99mTc using HYNIC, and showed high radiochemical purity of (96.90±2.27)%. The radiolabeling yield reached (96.32±2.08)%. The agent was excreted from kidney and only small amount could be seen in the liver. In the group of hepatocytes apoptosis, the ratios of liver/upper-limb in different imaging time were much higher than those of normal group. In apoptosis group, massive hepatocytes apoptosis could be seen in HE and Hoechst 33258 staining. Conclusion The apoptosis imaging agent ^99mTc-HYNIC-Annexin V prepared in this study can be used in vivo to show the apoptosis in the hepatocytes apoptosis models, suggestting that ^99mTc-HYNIC-Annexin V may be a promising agent for apoptosis imaging in clinical application.