Tamai Y, Ohizumi Y, Mori T
Department of Radiation Oncology, School of Medicine, Tokai University, Kanagawa, Japan.
Tokai J Exp Clin Med. 1996 Dec;21(4-6):171-6.
Although hyperthermia potentiates the effect of radiation, the combined effect decreases as the time between irradiation and hyperthermia increases. The purpose of this study was to prevent the rapid loss of efficacy by the local injection of epinephrine or peplomycin(PEP), two agents known as hyperthermic potentiators. In this study, Lewis lung carcinoma implanted in the foot of BDF1 mice was used for the assessment of tumor growth, skin reactions, and lung metastasis. The tumors were irradiated, then warmed in a water bath for 45 min. The retarding effects of hyperthermia on tumor growth and skin reactions were lost 2 days after irradiation. However, when PEP or epinephrine was injected before hyperthermia, tumor growth was distinctly delayed. The effect of epinephrine was greater than PEP and still showed enhancement 8 days after irradiation. For skin reactions, no significant enhancing effect was observed. Lung metastasis was significantly inhibited by the addition of epinephrine either 0 or 2 days after irradiation. In conclusion, the local administration of epinephrine combined with hyperthermia significantly retarded tumor growth without an increase in skin reactions or lung metastases. Possible mechanism underlying this phenomenon was discussed.
尽管热疗可增强放疗效果，但随着放疗与热疗之间时间间隔的增加，联合效应会降低。本研究的目的是通过局部注射肾上腺素或培普利欧霉素（PEP）这两种已知的热疗增效剂，来防止疗效的快速丧失。在本研究中，将接种于BDF1小鼠足部的Lewis肺癌用于评估肿瘤生长、皮肤反应和肺转移情况。对肿瘤进行照射，然后在水浴中加热45分钟。热疗对肿瘤生长和皮肤反应的延迟作用在照射后2天消失。然而，当在热疗前注射PEP或肾上腺素时，肿瘤生长明显延迟。肾上腺素的效果大于PEP，且在照射后8天仍显示出增强作用。对于皮肤反应，未观察到明显的增强效果。在照射后0天或2天添加肾上腺素均可显著抑制肺转移。总之，肾上腺素与热疗联合局部给药可显著延缓肿瘤生长，且不会增加皮肤反应或肺转移。讨论了该现象可能的潜在机制。
