缺氧对C57小鼠脑胶质瘤模型肿瘤形成及生存期的影响

Hypoxia improves tumor formation but reduces survival time in C57 mice implanted with glioma GL261 cells

目的探讨缺氧对C57小鼠胶质瘤肿瘤形成及生存期的影响。方法 1培养GL261胶质瘤细胞系,转染荧光素酶基因,制备GL261-Luc细胞。242只清洁健康级雌性C57小鼠[6周龄,体质量(17.5±2.3)g]脑内注射GL261-Luc细胞荷瘤,分成常氧饲养组(21%O2)和低氧饲养组(10%O2),每组21只,其中6只分别于7、14、21 d后行活体成像图像采集以观察小鼠肿瘤形成能力;另外15只用于生存期观察,时限30 d。3取材并HE染色观察肿瘤形成情况,免疫组化GFAP鉴定胶质瘤。结果活体成像显示缺氧饲养组小鼠有明显肿瘤形成,而常氧饲养组无肿瘤形成,计算颅内荷瘤细胞病毒活性并统计分析得缺氧饲养组肿瘤形成能力强于常氧饲养组(P<0.05);生存期分析显示缺氧饲养组小鼠平均生存期为22.5 d,生存率明显低于常氧饲养组(P<0.01);脑组织大体标本和HE染色发现缺氧组小鼠共18只有脑肿瘤形成,常氧组仅2只形成肿瘤,免疫组化GFAP胶质瘤鉴定示肿瘤内高表达。结论GL261胶质瘤细胞系C57小鼠成瘤模型缺氧饲养后肿瘤形成能力明显强于常氧饲养组,且生存率较常氧组更低,提示缺氧可以增加肿瘤恶性。

Objective To determine the effect of hypoxia on tumor formation and survival time in tumor-bearing C57 mice implanted with glioma GL261 cells. Methods Cultured glioma GL261 cells were transduced to express luciferase under blastieidin selection （5 μg/mL） to produce GL261-Luc cells. Then SPF C57 mice （n =42, female, 6 weeks old, weighing 17.5 ±2.3 g） implanted with GL261-Luc cells in the brain were randomized into 2 groups equally, fed under hypoxia condition （10% 02 ）, or normoxia （21% 02）. The tumor growth was observed by biolumineseence imaging （bli） in the days 7, 14 and 21 after injection （n =6 per group）. The remaining tumor-bearing mice （n = 15 per group） were observed for their survival within 30 d, and then the results were analyzed by Kaplan-Meier curve. HE staining was used to observe the tumor formation for those dead mice and survived mice within 30 d. Results Biolumineseence imaging showed that obvious tumor masses were developed in hypoxia-treated group, whereas no tumor was formed under normoxia. Measuring viral activity in the brain tumor cells indicated that the hypoxia-treated group had stronger capacity in tumor formation than the normoxia group （ P 〈 0.05 ）. The survival time of mice in hypoxia group was 22. 5 d, significantly lower than that of normoxia group （ P 〈 0. 01 ）. Gross and morphological observation found that there were 18 tumor masses in the mice of hypoxia group, but only 2 in the other group. Immunohistochemical staining showed that glial fibrillary acidic protein （GFAP） was highly expressed in the tumor masses. Conclusion Hypoxia promotes tumor formation and declines survival rate in glioma-bearing mice, when compared with the tumor-bearing mice living under normoxia, which indicating hypoxia improves malignancy in the implanted tumor.