Gibson S L, Ceckler T L, Bryant T G, Hilf R
Department of Biochemistry, University of Rochester Cancer Center, University of Rochester School of Medicine and Dentistry, NY 14642.
Cancer Biochem Biophys. 1989 Oct;10(4):319-28.
The effects of photodynamic therapy using 632 nm photoradiation emitted from an ion pumped dye laser system on the phosphate metabolite levels of rat mammary tumors were monitored by 31P-NMR spectroscopy. A dramatic decline to almost undetectable levels, in the ratio of whole tumor beta-ATP (NTP) to Pi was observed after systemic administration of 5 mg/kg Photofrin II 24 h prior to exposure of R3230AC rat mammary tumor to laser irradiation at 180 and 360 J/cm2 total fluence. This decline in ATP was accompanied by a concomitant increase in the levels of Pi relative to the total observable phosphate signals. Whole tumor pH was calculated from the chemical shift in inorganic phosphate using the water proton signal as reference. Under the same treatment conditions used to monitor the phosphate metabolites following Photodynamic Therapy, the pH of the tumor as a whole decreased approximately 0.35 units at the time when the beta-ATP to Pi ratios were lowest. This maximal decrease in whole tumor ATP levels and pH, which occurred at 4-6 h post irradiation, was followed by a gradual return to pre-treatment levels over a 24 h period. These results demonstrate that Photodynamic Therapy employing porphyrin photosensitization and monochromatic laser irradiation is effective in reducing both tumor high energy phosphate levels and pH. Depending on sensitizer dose and light fluence, metabolic inhibition, represented by depleted nucleoside triphosphates and elevated Pi, may be reversible.
使用离子泵浦染料激光系统发射的632 nm光辐射进行光动力疗法，对大鼠乳腺肿瘤磷酸盐代谢物水平的影响通过31P-NMR光谱进行监测。在以180和360 J/cm2的总能量密度对R3230AC大鼠乳腺肿瘤进行激光照射前24小时，全身给予5 mg/kg的卟吩姆钠（Photofrin II）后，观察到整个肿瘤的β-ATP（NTP）与Pi的比率急剧下降至几乎不可检测的水平。ATP的这种下降伴随着相对于总可观察到的磷酸盐信号，Pi水平的相应增加。以水质子信号为参考，根据无机磷酸盐的化学位移计算整个肿瘤的pH值。在用于监测光动力疗法后磷酸盐代谢物的相同治疗条件下，当β-ATP与Pi的比率最低时，整个肿瘤的pH值大约下降了0.35个单位。照射后4-6小时出现的整个肿瘤ATP水平和pH值的最大下降，随后在24小时内逐渐恢复到治疗前水平。这些结果表明，采用卟啉光敏化和单色激光照射的光动力疗法在降低肿瘤高能磷酸盐水平和pH值方面是有效的。根据敏化剂剂量和光能量密度，以核苷三磷酸耗尽和Pi升高为代表的代谢抑制可能是可逆的。
