Urano Muneyasu, Chen Yuchun, Humm John, Koutcher Jason A, Zanzonico Pat, Ling Clifton
Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, New York 10021, USA.
Radiat Res. 2002 Aug;158(2):167-73. doi: 10.1667/0033-7587(2002)158[0167:mottot]2.0.co;2.
Recently, a system that measures tissue oxygen tension using time-resolved luminescence-based optical sensors has become available commercially (Oxford Optronix, Oxford, England). Two experiments were conducted using this system. First, the oxygen tension distribution was measured in two tumor lines: a spontaneous mouse fibrosarcoma, FSa-II, and a human squamous cell carcinoma xenograft, FaDu. The area in which the pO(2) was equal to or lower than 2.5 mmHg was defined as the hypoxic lesion, and the hypoxic cell fraction was taken as the fraction of these measurements in a tumor. The measured hypoxic cell fractions were compared with those determined by the paired cell survival assay for tumors of various sizes. Second, the tumor tissue pO(2) was measured continuously after administration of two different anesthetics to evaluate the effect of these drugs on tissue pO(2). Results indicated a good agreement between the hypoxic cell fractions measured by this system and those determined by the paired cell survival curve assay for tumors smaller than approximately 500 mm(3). For tumors larger than approximately 500 mm(3), the hypoxic cell fractions measured by the oxygen probe system were higher than those measured by the paired cell survival assay. This may suggest that the hypoxic cell fraction measured by the oxygen probes included both hypoxic and necrotic areas in large tumors where necrotic lesions occupied a significant portion of the tumor. Continuous measurements of pO(2) after anesthesia (Nembutal, or ketamine plus xylazine) showed a consistent rise in the pO(2) during the first 20-30 min of measurement. Subsequently, the pO(2) values became constant or continued to rise slowly. For comparison, the tumor cell survivals were assayed after a dose of 20 Gy given in air at 5, 20 and 60 min after anesthesia. The result showed a decrease in cell survival only in tumors irradiated 20 min after an injection of Nembutal.
最近，一种使用基于时间分辨发光的光学传感器测量组织氧张力的系统已在商业上可用（牛津光电子公司，牛津，英国）。使用该系统进行了两项实验。首先，在两种肿瘤细胞系中测量氧张力分布：自发小鼠纤维肉瘤FSa-II和人鳞状细胞癌异种移植瘤FaDu。将pO₂等于或低于2.5 mmHg的区域定义为缺氧病变，缺氧细胞分数作为肿瘤中这些测量值的分数。将测量的缺氧细胞分数与通过配对细胞存活试验确定的不同大小肿瘤的分数进行比较。其次，在给予两种不同麻醉剂后连续测量肿瘤组织pO₂，以评估这些药物对组织pO₂的影响。结果表明，对于小于约500 mm³的肿瘤，该系统测量的缺氧细胞分数与通过配对细胞存活曲线试验确定的分数之间具有良好的一致性。对于大于约500 mm³的肿瘤，氧探针系统测量的缺氧细胞分数高于通过配对细胞存活试验测量的分数。这可能表明，氧探针测量的缺氧细胞分数包括大肿瘤中的缺氧和坏死区域，其中坏死病变占据肿瘤的很大一部分。麻醉（戊巴比妥或氯胺酮加赛拉嗪）后连续测量pO₂显示，在测量的前20 - 30分钟内pO₂持续升高。随后，pO₂值变得恒定或继续缓慢上升。为了进行比较，在麻醉后5、20和60分钟在空气中给予20 Gy剂量后测定肿瘤细胞存活率。结果显示，仅在注射戊巴比妥后20分钟照射的肿瘤中细胞存活率降低。
