【摘要】 目的:分析99Tcm直接标记法标记重组膜联蛋白V(99Tcm-rh-Annexin Ⅴ)在小鼠体内的生理性分布特点,探讨其评价单次化疗后肿瘤细胞的凋亡状况的可行性。方法:采用直接标记法标记rh-Annexin Ⅴ;应用SPECT及井型闪烁探测器观察不同时间示踪剂在A组(正常小鼠)体内的生理性分布状况,并计算每克组织百分注射剂量率(%ID/g);B组为荷瘤组,将小鼠肝癌细胞(Hca-F25)接种于小鼠右腋下部位;随机分为4个亚组(B1,n=6;B2,n=5;B3,n=3;B4,n=3),肿瘤生长至直径约1cm时,B1、B3组一次性接受环磷酰胺(cyclophosphamide)腹膜内注射,剂量为150mg/kg;20h后,B1、B2组同时由鼠尾静脉注入99Tcm-rh-Annexin Ⅴ(剂量为5.55MBq/0.5μg/0.1ml/只),B3、B4组只注入相同放射性活度的高锝酸盐及还原剂,而不标记Annex-in Ⅴ;6h后分别显像、处死、取材;比较各亚组间肿瘤组织的%ID/g、靶/本底比值(T/M、T/B)以及流式细胞分析凋亡细胞(Annex-in Ⅴ阳性/PI阴性)百分比。结果:99Tcm-rh-Annexin Ⅴ在肾脏中的生理性分布最高,肝脏中分布较少,而其它组织及脏器中分布则甚少。B1组瘤体内%ID/g及T/M、T/B比值明显高于其余3个亚组(P<0.05),而B2、B3、B4组之间无明显差异(P>0.05);B1组肿瘤组织%ID/g与凋亡细胞百分比呈明显正相关(r=0.813,P=0.04),而B2、B3、B4组则不相关(r=0.386,P=0.241)。结论:单次化疗后,肿瘤组织内99Tcm-rh-Annexin Ⅴ的摄取明显增加,且其摄取的程度与肿瘤组织内凋亡细胞的多少呈明显正相关;99Tcm-rh-Annexin Ⅴ显像可以较为准确地反映化疗后早期肿瘤组织细胞凋亡的状况。更多还原

【Abstract】 Objective: To analyse the biodistribution of 99Tcm directly labelled recombinant human Annexin Ⅴ(99Tcm-rh-Annexin Ⅴ) in mice and to determine the effectiveness of imaging with this agent as a reflection of the degree of apoptosis after the first dose of chemotherapy. Methods: The biodistribution of 99Tcm-rh-Annexin Ⅴ was studied using purebred 615 mice(group A). After SPECT imaging, the animals were sacrified. The tissue samples were weighed and radioactivity was determined with a well-type scintillation counter. The accumulation of 99Tcm-rh-Annexin Ⅴ in the tissues was expressed as %ID/g(percentage activity of injection dose per gram of tissue). Eight days after being inoculated with allogenic hepatoma cells(Hca-F25) into the subcutaneos tissue of the right axillary fossa, the mice(group B)were randomly divided into four groups(B1, n=6; B2, n=5; B3, n=3; B4, n=3). Group B1 and group B3 received a single dose of cyclophosphamide(150mg/kg, intraperitoneally). Group B1 and group B2 were injected 99Tcm-rh-Annexin Ⅴ(5.55MBq/0.5μg/0.1ml/per mouse) intravenously 20hrs later, at the same time group B3 and group B4 received the same doses of 99Tcm without being labelled with Annexin Ⅴ. Radioactivity in tissues(tumor, blood, muscle) was determined 6hrs later. Apoptotic cells were detected with Annexin Ⅴ/PI flow cytometry. The morphological changes of the apoptotic hepatoma cells were observed by light and transmission electron microscopies. Results: The kidney had the highest concentration of radioactivity at all time points. On the other hand the liver uptake was lower and other organs showed the least concentration of 99Tcm-rh-Annexin Ⅴ. Cyclophosphamide treatment significantly increased the tumor uptake of 99Tcm-rh-Annexin Ⅴ[(0.48±0.16)%ID/g for group B1 and 0.30±0.06 for group B2, P<0.05]. Tumor uptake of 99Tcm-rh-Annexin Ⅴ of group B1 correlated well with the number of Annexin Ⅴ/PI-positive cells in the tumor(r=0.813, P=0.04), on the other hand, group B2, group B3 and group B4 had no correlation(r=0.386, P=0.241). Conclusion: Tumor uptake of 99Tcm-rh-Annexin Ⅴ was significantly increased by a single dose of cyclophosphamide treatment, and the increase was concordant with the number of Annexin Ⅴ/PI-positive cells in tumor. The current results are suggestive of the utility of 99Tcm-rh-Annexin Ⅴ as a noninvasive means to assess tumor response, although further testing is required.更多还原