恩度不同给药时相对肺癌裸鼠移植瘤辐射增敏效应研究

Endostatin Combined with Radiotherapy for Treating Lung Cancer at Different Times of In Vivo Administration in Nude Mice

目的:探讨恩度不同加药时间对肺癌裸鼠移植瘤的辐射增敏效果。方法:以A549裸鼠移植瘤为载体,随机分成6组:对照组(A),单纯照射组(B),单纯恩度组(C),照射前给药组(D),同时给药组(E)和照射后给药组(F)。恩度每只按20mg/kg·d^(-1)给予,连续14d。照射剂量200 cGy/f,共计10次,5次/w。D、F组给药14 d后和前照射14 d,E组照射前1h给药,连续14 d。观察肿瘤的生长速度和瘤体大小的变化,处理后第15天及29天免疫组织化学法检测MVD、MMP-2、VEGF的表达情况,免疫荧光双重染色检测肿瘤细胞及内皮细胞的凋亡。结果:不同处理组移植瘤体积或重量抑瘤率分别为B组:49.48%,51.13%;C组:25.48%,34.39%;D组:66.69%,74.66%;E组:76.37%,88.69%;F组:56%,66.52%。联合组与其他组相比差异均有统计学意义(P<0.05)。第15天时照射同时加药组(E),单纯加药组(C)与对照组(A)VEGF的表达差异有统计学意义(P<0.05)。第29天时照射同时加药组(E)与照射前加药组(D)、照射后加药组(F)的表达差异有统计学意义(P<0.05),但后两者表达无显著性差异。MMP-2的变化趋势与VEGF一致。第15天时照射同时加药组(E),单纯加药组(C)与对照组(A)MVD的数量差异有统计学意义(P<0.05)。第29天时照射同时加药组(E)与照射前加药组(D),照射后加药组(F)的表达差异有统计学意义(P<0.05)。免疫荧光双重染色显示第15天时单纯加药组(C),单照射组(B)以及联合组肿瘤细胞和内皮细胞的凋亡增加,与对照组相比差异有统计学意义(P<0.05)。第29天时联合组中,照射同时加药组与其他组均差异有统计学意义。结论:恩度对肺腺癌A549移植瘤辐射增敏作用明确,其中,又以辐射同时给药组增敏效应最强。VEGF、MMP-2和MVD的表达变化是其重要机制。

Objective： To study different treatment sequences by observing the radiosensitizing effect on transplanted tumors and to provide proof for clinical practice. Methods： Lung adenocarcinoma xenografts were used in nude mice models, and the changes in xenograft sizes were measured. All mice with average tumor volumes of 200 mm3 to 300 mm3 were randomized into six groups （ n =5 ）. Endostatin （ ES ） was administered to A549 lung cancer ceils in three different ways, namely, before irradiation （ method Ⅱ ）, upon irra- diation （ method Ⅱ ）, and after irradiation （ method Ill ）, to establish the radiosensitizing effects. The ES-treated groups were given 20 mg·kg^-1 of ES daily via subcutaneous injection for 14 days. The control group （ Group A ） was given an equivalence of normal sodium for 14 days. The radiotherapy group （ Group B ） was exposed to 20 Gy/ 10 f X-ray irradiation for 14 days, at lf/d and 5f/w. Group C was treated with ES alone at the abovementioned dosage via subcutaneous injection. Groups D, E, and F, were given ES via subcutane- ous injection before, during, and after irradiation, respectively, and exposed to 20Gy/10f X-ray irradiation at lf/d and 5f/w. Treatment was conducted daily for 14 days. Then, 15 and 29 days after the treatment, the mice were sacrificed and the tumor tissues were ob- tained. The tissues were used in immunohistochemical staining for CD31, MMP - 2 and vascular endothelial growth factor （ VEGF ）. Results： The growth of the lung adenocarcinoma xenografts of the mice was significantly inhibited by the combined therapy and irradia- tion. The tumor weight in Group E as lower compared with that of any other group at 15 or 29 days after the treatment. The inhibition rate was also the highest in Group E. The capillary density and MMP - 2 and VEGF expression levels degraded in all groups with ES treatment. Immunohistochemical assay showed positive VEGF expression in the tumors of each group, as well as the differences be- tween the treatment and control groups （ P 〈 0.05 ）. Conclusion： In this study, the inhibitory action in the groups treated with ES andexposed to irradiation was superior compared with those of the groups exposed to radiotherapy alone or simple ES therapy. In particu- lar, the group treated with ES and exposed to irradiation had the optimal radiosensitizing effect compared with all other groups.