^99Tc^m-Annexin B1探测荷瘤鼠化疗后肿瘤细胞凋亡的实验观察

目的：探讨^99Tc^m-Annexin B1探测化疗后肿瘤细胞凋亡的潜力与可行性。方法：乳腺癌细胞MDA-MB-435荷瘤小鼠经大剂量（30mg／kg）紫杉醇单次化疗后，注射^99Tc^m-Annexin B1，计算化疗后不同时间（0、5、10、15、20和25h）每克肿瘤组织摄取^99Tc^m-Annexin B1的百分注射剂量率（％ID／g）。肉瘤细胞W256荷瘤大鼠经大剂量（200mg／kg）环磷酰胺单次化疗后24h注射^99Tc^m-Annexin B1，对照组荷瘤大鼠注射生理盐水；行SPECT平面显像观察肿瘤摄取情况。结果：乳腺癌荷瘤小鼠化疗后15h，肿瘤摄取^99Tc^m-Annexin B1达高峰，由0h的（0．15±0．013）％ID／g上升至（0．22±0．026）％ID／g。肿瘤对^99Tc^m-Annexin B1的摄取与肿瘤细胞凋亡指数（AI）具有相关性，r=0．88，P〈0．01。W256细胞荷瘤大鼠化疗后24h显像发现，肿瘤对^99Tc^m-Annexin B1的摄取较对照荷瘤大鼠显著升高，对照组的肿瘤与非肿瘤摄取比值（T／B）为1．39±0．21，化疗组为2．57±0．43。结论：^99Tc^m-Annexin B1对探测化疗后肿瘤细胞凋亡具有潜力与可行性。

Detection of tumor cell apoptosis induced by chemotherapy with ^99Tc^m-Annexin B1

OBJECTIVE： To explore the potential and feasibility of ^99Tc^m Annexin B1 for the detection of tumor cell apoptosis induced by chemotherapy. METHODS： The uptake rate（%ID/g） of ^99Tc^m-Annexin B1 by tumor cell 0, 5, 10, 15, 20 and 25 hours after chemotherapy with a large single dose of paclitaxel （30 mg/kg） was investigated in tumor-bearing mice with MDA-MB-435 cells. Planar scintigraphy with ^99Tc^m-Annexin B1 was used to detect tumor apoptosis in W256 cell tumor-bearing rats. The rats were treated with a large single dose of cyelophosphamide （200 mg/kg）, or treated with normal saline as control. RESULTS： The biodistribution analyses revealed an uptake peak of ^99Tc^m-Annexin B1 at 15 h after the paclitaxel treatment in MDA-MB435 mice, increasing from （0.15±0.013）%ID/g at 0 h （control） to （0.22±0.026）%ID/g at 15 h after the chemotherapy. Importantly, there was a significant correlation between tumor uptake of ^99Tc^m-Annexin B1 and AI determined by TUNEL analyses （r =0.88, P〈0.01）. The scintigraphy in W256 rats showed increased radioactivity accumulation in the tumor at 24 h after the chemotherapy compared with the control. The tumor-to background ratio （T/B） increased from 1.39±0.21 in the untreated rats to 2.57±0.43 in the chemotherapy rats. CONCLUSIONS： ^99Tc^m- Annexin B1 as a noninva sive means to detect tumor ceil apoptosis induced by chemotherapy is feasible. ^99Tc^m-Annexin B1 can be used to assess tumor response to chemotherapy.