The biological effect of spinal intensity modulated radiation therapy on bone tissue at different doses in Beagles / 中华放射医学与防护杂志

ABSTRACT

Objective To explore a safe dose range of spinal IMRT by comparing the cell damage in Beagles at different dose levels.Methods Thirty Beagles were randomly divided into 5 groups.The Beagle clinical model of tumor was established in the ninth and tenth thoracic spine.The Beagles were subjected to IMRT with the total doses of 0,40,50,60,70 Gy,respectively.The samples of spine were taken out from the same locum of the ninth and tenth thoracic spine at 3 month after radiation.All the samples were observed by the hematoxylin-eosin staining,and the VEGF expression in spine was evaluated by immunohistochemistry.Terminal deoxynucleatidyl transferase mediated dUTP nick and labeling (TUNEL) technique was used to examine the apoptotic cells in the spine.Results The osteocytes in the spine showed reversible injury in 40 Gy group,and cell apoptosis in 50,60,70 Gy groups.Compared with 40 Gy group,the rates of lacuna were increased in 50,60,70 Gy groups(F =2.57,P ＜0.05),as well as the cell apoptotic rates(F =3.52,P ＜ 0.05) and the expression of VEGF (F =3.64,P ＜ 0.05),but there were no significant differences among 50,60,70 Gy groups (P ＞ 0.05).Conclusions The late radiotherapy response of the spine was obviously observed at 3 month after radiation,especially at 50 Gy.