de Vrind H H, Haveman J, Wondergem J
Department of Radiotherapy, University of Amsterdam, The Netherlands.
Int J Radiat Biol. 1991 Jan;59(1):251-7. doi: 10.1080/09553009114550221.
A 5 mm segment of the rat sciatic nerve was treated at 38 or 43 degrees C for 30 min using a brass thermode. This pretreatment was followed by a test heat treatment at 45 degrees C. Different intervals between the pretreatment and test treatment were studied. The effect of fractionated hyperthermia on the motor function of rat sciatic nerve was evaluated using a functional assay, the toe-spreading test. Both pretreatments led to thermal resistance of the nerve, which was maximal 24 h after the pretreatment. Thermal resistance, induced at 38 degrees C, did not show any decay over a period of 6 weeks. Thermal resistance, induced at 43 degrees C, decayed slowly, but after a 6-week interval between priming and test heat treatment thermal resistance was still observed. As the resistance induced by a mild heat pretreatment is transient, we considered this to be thermotolerance. We accounted for the thermal resistance induced by the 38 degrees C pretreatment in the calculation of the thermal tolerance ratio (TTR) after mild heat treatment at 43 degrees C. Maximal thermal tolerance was observed 24 h after mild heat with a TTR of 3.4 +/- 0.6. The TTR after a 6-week interval had declined to 1.4 +/- 0.3.
使用黄铜热电极将大鼠坐骨神经的5毫米节段在38或43摄氏度下处理30分钟。该预处理之后是在45摄氏度下进行的测试热处理。研究了预处理和测试处理之间的不同间隔。使用功能性测定法（即趾展试验）评估了分次热疗对大鼠坐骨神经运动功能的影响。两种预处理均导致神经产生热抗性，在预处理后24小时达到最大值。在38摄氏度诱导的热抗性在6周内未显示任何衰减。在43摄氏度诱导的热抗性衰减缓慢，但在引发热疗和测试热疗之间间隔6周后仍观察到热抗性。由于轻度热预处理诱导的抗性是短暂的，我们认为这是热耐受性。在计算43摄氏度轻度热疗后的热耐受比（TTR）时，我们考虑了38摄氏度预处理诱导的热抗性。轻度热疗后24小时观察到最大热耐受性，TTR为3.4±0.6。6周间隔后的TTR已降至1.4±0.3。
