논문검색
Author Won Dong Kim, M.D. and Woo Yoon Park, M.D.
Place of duty Department of Radiation Oncology, Chungbuk National University College of Medicine, Cheongju, Korea
Title The Effect of Pentoxifylline on Radiobiological Parameters in the Rat Radiation Myelopathy
Publicationinfo Cancer Res Treat 2006 Dec; 038(04): 229-233.
Key_word Pentoxifylline, α/β, T1/2, Rat radiation myelopathy
Full-Text
Abstract Purpose: There is great recent interest in the potential value of using pentoxifylline (3,7-dimethyl-1(5-oxyhexyl)- xanthine, PTX) as an inhibitor of radiation-induced late normal tissue damage. The effects of PTX on the radiobiological parameters (α/β ratio, repair half time T1/2) of radiation myelopathy were studied in a rat model. Materials and Methods: Anesthetized Sprague-Dawley rats received irradiation to 2 cm of their cervical spines with using a 6MV LINAC (dose rate: 3 Gy/min). Radiation was administered in single, two, four and eight fractions with a fraction interval of 24 h with or without PTX. PTX was added to the rats' distilled drinking water at a concentration of 2 g/L; the water was consumed ad libitum. After tabulation of the ED50 (the estimated dose needed to produce 50% paralysis in a group of irradiated animals), α/β could be estimated from the ratio of the slope to the intercept of the reciprocal-dose plot. Subsequently, the repair half time T1/2 was obtained from the data of the experimental group that received a pair of 7 Gy fractions on each day, separated by intervals of 4 and 8 h. Results: The α values calculated for RT alone and RT⁢PTX were almost the same. We noticed that the β value for the RT⁢PTX was lower than that for RT alone. So, the α/β ratio for the RT⁢PTX was higher. The T1/2 obtained from monoexponential model was 3.27 and 2.58 h for RT alone and RT⁢PTX, respectively. Conclusion: PTX increased the α/β ratio and it decreased the T1/2 of radiation myelopathy, suggesting that a decreasing fractionation sensitivity occurred. This implies that PTX, which distinctly acts upon the bending region of the high dose, may be expected to protect the spinal cord with a larger fraction size. (Cancer Res Treat. 2006;38:229-233)
출판정보 대한암학회지 2006 Dec; 038(04): 229-233.