TY - JOUR
T1 - Neurological observations after local irradiation and hyperthermia of rat lumbosacral spinal cord
AU - Sminia, P
AU - Hendriks, J J
AU - Van der Kracht, A H
AU - Rodermond, H M
AU - Haveman, J
AU - Jansen, W
AU - Koedooder, K
AU - Franken, N A
PY - 1995/4/30
Y1 - 1995/4/30
N2 - PURPOSE: Investigation of the effects of hyperthermia on the radiation response of rat lumbosacral spinal cord with respect to: (a) incidence of paralysis, (b) latency, (c) histopathology, and (d) tumor induction.METHODS AND MATERIALS: Rat lumbosacral spinal cord with the cauda equina was single-dose irradiated with 15 to 32 Gy of x-rays. Hyperthermia for 30 min at a spinal cord temperature of 41.1, 42.3, and 42.6 +/- 0.4 degrees C was applied 5 to 10 min after irradiation by means of a 434 MHz microwave applicator. Animals were observed for 21 months while recording myelopathy and development of tumors.RESULTS: The latent period for hind leg paralysis decreased with increasing radiation dose from 359 +/- 31 days (n = 9) after 20 Gy to 200 +/- 4 days (n = 5) after 32 Gy. Hyperthermia enhanced the radiation response of the lumbosacral spinal cord as evidenced by shortening of the latent period for paralysis and a decrease in the biological effective dose. After 20 Gy followed by 30 min 41.1 degrees C, latency was diminished to 214 +/- 16 days (n = 7, p < 0.001 vs. 20 Gy alone). The ED50 was 21.1 Gy, which was diminished to values between 16 and 17 Gy if radiation was followed by hyperthermia, giving a thermal enhancement ratio between 1.24 and 1.32. Histopathological examination of the spinal cord after combined treatment of x-rays and hyperthermia showed necrosis of nerve roots. Irradiation with 16, 20, 24, and 28 Gy (n = 77) alone led to tumor induction in 17 +/- 8% of the animals (pooled data). If followed by hyperthermia (n = 96), it was increased to 33 +/- 12% (p < 0.01). Most tumors induced by radiation and hyperthermia were sarcomas.CONCLUSION: First, the radiation response of rat lumbosacral spinal cord was enhanced by heat. Second, latency for paralysis was shortened in the lower dose range. Third, no difference in pathology between x-rays alone or in combination with hyperthermia. Fourth, hyperthermia did increase radiation carcinogenesis.
AB - PURPOSE: Investigation of the effects of hyperthermia on the radiation response of rat lumbosacral spinal cord with respect to: (a) incidence of paralysis, (b) latency, (c) histopathology, and (d) tumor induction.METHODS AND MATERIALS: Rat lumbosacral spinal cord with the cauda equina was single-dose irradiated with 15 to 32 Gy of x-rays. Hyperthermia for 30 min at a spinal cord temperature of 41.1, 42.3, and 42.6 +/- 0.4 degrees C was applied 5 to 10 min after irradiation by means of a 434 MHz microwave applicator. Animals were observed for 21 months while recording myelopathy and development of tumors.RESULTS: The latent period for hind leg paralysis decreased with increasing radiation dose from 359 +/- 31 days (n = 9) after 20 Gy to 200 +/- 4 days (n = 5) after 32 Gy. Hyperthermia enhanced the radiation response of the lumbosacral spinal cord as evidenced by shortening of the latent period for paralysis and a decrease in the biological effective dose. After 20 Gy followed by 30 min 41.1 degrees C, latency was diminished to 214 +/- 16 days (n = 7, p < 0.001 vs. 20 Gy alone). The ED50 was 21.1 Gy, which was diminished to values between 16 and 17 Gy if radiation was followed by hyperthermia, giving a thermal enhancement ratio between 1.24 and 1.32. Histopathological examination of the spinal cord after combined treatment of x-rays and hyperthermia showed necrosis of nerve roots. Irradiation with 16, 20, 24, and 28 Gy (n = 77) alone led to tumor induction in 17 +/- 8% of the animals (pooled data). If followed by hyperthermia (n = 96), it was increased to 33 +/- 12% (p < 0.01). Most tumors induced by radiation and hyperthermia were sarcomas.CONCLUSION: First, the radiation response of rat lumbosacral spinal cord was enhanced by heat. Second, latency for paralysis was shortened in the lower dose range. Third, no difference in pathology between x-rays alone or in combination with hyperthermia. Fourth, hyperthermia did increase radiation carcinogenesis.
KW - Animals
KW - Cauda Equina/radiation effects
KW - Dose-Response Relationship, Radiation
KW - Female
KW - Hyperthermia, Induced/adverse effects
KW - Neoplasms, Radiation-Induced/etiology
KW - Paralysis/etiology
KW - Radiation Dosage
KW - Radiation Tolerance
KW - Rats
KW - Rats, Wistar
KW - Spinal Cord/radiation effects
KW - Time Factors
U2 - 10.1016/0360-3016(95)00519-5
DO - 10.1016/0360-3016(95)00519-5
M3 - Article
C2 - 7721613
VL - 32
SP - 165
EP - 174
JO - International Journal of Radiation Oncology Biology Physics
JF - International Journal of Radiation Oncology Biology Physics
SN - 0360-3016
IS - 1
ER -