Evaluation of insulin-like growth factor-1 for prevention of radiation-induced spinal cord damage.
OBJECTIVE
To test whether insulin-like growth factor-1 (IGF-1) ameliorates radiation-induced spinal cord myelopathy and to establish the dose-effect relationship for this growth factor which has not been administered in conjunction with spinal cord irradiation to date.


METHODS
Animal experiments were conducted to test the feasibility of IGF-1 injection in a model of cervical spinal cord irradiation in adult Fisher F-344 rats and to determine the most effective dose level of IGF-1. Irradiation was given in two fractions (16 Gy followed by 18 Gy) and animals were examined for the development of paresis (follow-up 12 months).


RESULTS
The dose-finding experiment revealed significant differences in the incidence of radiation myelopathy (RM). The most effective dose of IGF-1 was 50 microg per day.


CONCLUSIONS
IGF-1 showed promising activity as a radioprotective agent in a model of high-dose spinal cord irradiation. Further studies are needed to examine the results with multiple small doses of radiation as widely applied in clinical protocols.
Nieder
Carsten
C
Department of Radiation Oncology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany. cnied@hotmail.com
Andratschke
Nicolaus
N
Price
Roger E
RE
Rivera
Belinda
B
Kian Ang
K
K
D000818:Animals; D004307:Dose-Response Relationship, Radiation; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D007278:Injections, Spinal; D007334:Insulin-Like Growth Factor I / Q000008:administration & dosage*; D010291:Paresis / Q000503:physiopathology; D011833:Radiation Injuries, Experimental / Q000473:pathology / Q000517:prevention & control*; D011836:Radiation Tolerance / Q000187:drug effects; D011837:Radiation-Protective Agents / Q000008:administration & dosage*; D051381:Rats; D011916:Rats, Inbred F344; D013116:Spinal Cord / Q000473:pathology / Q000528:radiation effects*; D013997:Time Factors
D011837:Radiation-Protective Agents; D007334:Insulin-Like Growth Factor I