凋亡显像剂99m Tc-HYNIC-annexin V对肿模型化疗疗效早期评价的可行性

摘要

Objective To evaluate if 99mTc-HYNIC-annexin V may be used to detect the early chemotherapeutic effect and to determine the best timing for detecting apoptosis in rico. Methods Annexin V was labeled with 99mTc using HYNIC as a bifunctional agent. Normal Kunming mice received inoculation of Ehrlich ascites cells into the fight upper limb. After the tumor reached 1 cm in diameter, the mice were randomly divided into saline treatment group as control and cyclophesphamide (150mg/kg injected intraperitoneally) treatment group. 99mTc-HYNIC-annexin V was injected intravenously at 1 h and 24 h after treatment. Region of interest technique (ROI) from the SPECT images taken at different time was used to get the ratio of tumor/limb in each group. TUNEL staining was used to detect apoptotic cells and the rates of positive stained cells were calculated. Results After treatment with saline, only little amount of the radiolabeled tracer could be seen in the tumor and showed weak image of the tumor. But after 24 h of treatment with cyclophosphamide, clear imnge on the tumor could be seen. 24 h after the treatment of cyclophosphamide, the ratio of tumor/limb was (6.27±0.24) which was much higher than that at 24 h after treatment with saline (2.36±0.18) and that at 1 h after cyclophosphamide treatment (4.00±0.38). At 24 h after cyclophosphamide treatment, TUNEL staining showed a significantly higher rate of apoptotic cells in the mice. Conclusion 99mTc-HYNIC-annexin V can be used as an apoptosis-imnging agent to detect and evaluate the early curative effect after chemotherapy. The effective detection of apoptotic response in tumor with 99mTc-HYNIC-armexin V requires a 24 h interval after chemotherapy. SPECT images can be obtained at 60 vain after injection of the imaging agent. It suggests that 99mTc-HYNIC-annexin V may become a promising agent for apoptosis-imaging in clinical application.%目的 评价凋亡显像剂99mTc-HYNIC-annexin V在肿瘤动物模型中对化疗疗效早期评估的可行性.方法 人膜联蛋白V(annexin V)通过双功能螯合剂联肼尼克酰胺(HYNIC)进行99mTc标记.在正常昆明小鼠右上肢接种Ehrlich腹水癌细胞,至肿瘤生长至1 cm后,随机分为生理盐水处理组和环磷酰胺处理组(150 mg/kg),并分别于处理后1 h和24 h时注射99mTc-HYNIC-annexin V.注射后30、60、180、360 min进行双探头单光子发射计算机断层仪(SPECT)显像.图像分析采用感兴趣区(ROI)技术,计算右上肢肿瘤部位与右下肢计数比值(肿瘤/下肢).采用原位缺口末端标记(TUNEL)法检测肿瘤组织凋亡细胞.结果 在不同处理时间,生理盐水处理组的肿瘤部位仅有少量显像剂分布.环磷酰胺处理组在处理1 h后,肿瘤部位显像剂分布少量增加;24 h后,肿瘤部位显像剂分布明显增加,显影清晰.环磷酰胺处理24 h组的肿瘤/下肢比值(6.27±0.24)明显高于生理盐水24 h处理组(2.36±0.18)和环磷酰胺1 h处理组(4.00±0.38).环磷酰胺处理24 h后,TUNEL染色可见大量癌细胞凋亡.结论 99mTc-HYNIC-annexin V是一种可以早期监测化疗药物治疗效果的核素凋亡显像剂,在化疗药物应用24 h后就可以进行有效探测,并在注射显像剂后60 win即可获得清晰的图像.