Assessment of the Response of murine NR-S1 tumor following irradiation monitored by P-31 NMR Spectroscopy

本项目的目的是评估x或中子辐照对P-31核磁共振波谱监测的小鼠NR-S1肿瘤的反应，并从能量代谢、细胞内ph的角度阐明该肿瘤的放射敏感性。为此，我们设置了3名受试者，并并行进行了实验。在肿瘤生长过程中，代谢剥夺区域的发展可能以缺氧为特征，并导致高能磷酸盐的减少，包括ATP、磷酸肌酸（PCr）和ph - ii。单次X或中子照射后NR-S1肿瘤的反应单次X照射（25Gy, 5gy）后，Pi/PCr在3-4小时内出现初始升高。照射后2- 3天，Pi/PCr显著降低。这种现象可能是肿瘤细胞的再氧化代谢发生了变化。相比之下，剂量（10GY, 2gy）小于X-辐照剂量的中子辐照后也有相同的变化。分次x射线照射后NR-S1肿瘤的反应在均匀分次x射线照射下，能量代谢的变化并不比单次剂量照射的变化明显。在辐照后2 ~ 3天，各组能量状态恢复率基本相同，辐照间隔为4小时或24小时。相比之下，24小时间隔组的恢复最为显著。总之，P-31 MRS在肿瘤能量代谢的非侵入性研究中具有相当大的意义，并影响包括放射治疗在内的大多数治疗方式的结果。

The purpose of the present project is to assess the response of X-or Neutron irradiation to Murine NR-S1 tumor monitored by P-31 NMR Spectroscopy and to elucidate the radiosensitivity of this tumor from the point of energy metabolism, intracellular pH. Toward this goal, 3 subjects were set and have been carried out in parallel.I. Normal growth of NR-S1 tumor During tumor growth, areas of metabolic deprivation develop which may be characterized by hypoxia and resultant reduction in high energy phosphates, including ATP, phosphocreatine (PCr) and pH.II. Response of NR-S1 tumor following a single dose of X or Neutron irradiation After single dose of X-irradiation (25Gy, 5OGy), initial increase of Pi/PCr within 3-4 hours was occurred. The significant reduction of Pi/PCr was noted 2- 3 days after following irradiation. This phenomena may be a change in tumor cell metabolism with reoxygenation. In contrast, the same changes were noted after Neutron-irradiation in the doses (10GY, 2OGy) less than the dose of X- irradiation.III. Response of NR-S1 tumor following fractionated X-irradiation In the even fractionated X-irradiation, the changes of energy metabolism were not significant more than the changes of the single dose irradiation. With 2 fractions of 25 Gy at interval of 4 hours or 24 hours, the recover rates of energy status 2-3 days after irradiation were mostly the same within these groups. In contrast, in the group of the split interval of 24 hours, the recovery was noted mostly significant.In conclusion, P-31 MRS has been considerable for non-invasive investigation of tumor energy metabolism and which influence the outcome of most therapeutic modalities, including radiotherapy.