Katoh T
Department of Radiology, Kansai Medical University.
Nihon Igaku Hoshasen Gakkai Zasshi. 1990 Jun 25;50(6):661-8.
The hypoxic cell fraction in tumors is considered to be responsible for radioresistance. Estimating the population of the hypoxic cell fraction in tumor could develop the effective means to predict radiosensitivity. In this study, nitroacridine (fluorescent dye) was tested to estimate hypoxic status in single cells and in spheroids. The oxygen concentration in the medium was measured by oxygen electrodes utilizing polarography method, mean while that in cells was calculated from the fluorescence intensity of the dye. The fluorescent spectra from cells showed the same pattern in spite of the changed oxygen concentration in medium, on the other hand its intensity was dependent upon the oxygen concentration. Using a fixed nitroacridine concentration and a fixed staining time, oxygen concentration of cells could be determined within range from 0.1 to 1.0% values. These values are almost the same as the oxygen concentration of the radioresistant tumor cells. Thus, the fluorescent method we used in this study is considered to be useful to estimate radioresistance of tumor. However, fluorescent intensity would alter when used different cell lines, because of different cellular activity of nitroreductase.
肿瘤中的乏氧细胞部分被认为是导致放射抗性的原因。估计肿瘤中乏氧细胞部分的数量可以开发出预测放射敏感性的有效方法。在本研究中，测试了硝基吖啶（荧光染料）以估计单细胞和球体中的乏氧状态。通过利用极谱法的氧电极测量培养基中的氧浓度，同时根据染料的荧光强度计算细胞中的氧浓度。尽管培养基中的氧浓度发生了变化，但细胞的荧光光谱显示出相同的模式，另一方面其强度取决于氧浓度。使用固定的硝基吖啶浓度和固定的染色时间，可以在0.1%至1.0%的值范围内确定细胞的氧浓度。这些值与放射抗性肿瘤细胞的氧浓度几乎相同。因此，我们在本研究中使用的荧光方法被认为可用于估计肿瘤的放射抗性。然而，由于硝基还原酶的细胞活性不同，当使用不同的细胞系时，荧光强度会发生变化。
