骨放射性损伤血液供应及代谢改变的实验研究

Experimental studies of blood flow and metabolism changes in γ-ray induced bone injury

目的 探讨射线照射后近、远期骨局部血流及代谢的变化。方法 60 Co (30Gy)一次性照射兔右后肢胫骨 ,分别于致伤后第 1、3、6、12、2 4和 5 2周行局部血流量 (RBF)测定、动脉灌注显像和延迟骨显像。结果 照射后伤侧RBF逐渐增加 ,3周时为对照侧的 2倍 ,6周时两侧接近 ,5 2周时仅为对照侧的 2 7.8%。致伤后 3周 ,受照侧时间 放射性曲线明显高于对照侧 ,12周开始降低 ,5 2周时约为对照侧的 2 5 %。照射后 3周伤侧延迟骨显像ROI计数明显增加 (P <0 .0 1) ,6周时两侧差异无显著性 (P >0 .0 5 ) ,12周后受照侧明显降低 (P <0 .0 1)。结论 放射性骨损伤早期受照局部骨血液供应增加伴成骨代谢活跃 ,中晚期局部血循环及成骨代谢明显低下。

Objective To investigate regional blood flow (RBF) and metabolism changes in the short- and long-term after bone irradiation injury. Methods The tibia of the rabbits on the right side was irradiated with 60 Co γ ray at a dose of 30 Gy. The tibia on the other side was taken as the control. RBF measurement, perfusion imaging and delayed bone imaging were respectively performed at the 1st, 3rd, 6th, 12th, 24th and 52nd week after the irradiation. Results The RBF of injured side gradually increased after irradiation, and reached as two times as the level of the control at the 3rd week, and approached to the similar values on both sides at the 6th week, and then became only 27.8% of the value of the control at the 52nd week, the differences of RBF between two sides at all phases were significant or very significant( P <0.05～0.01). Time-activity curve of perfusion imaging on irradiated side was apparently higher than that on control side at the 3rd week after irradiation and slightly higher at the 6th week, began to decrease at the 12th week and was only about 25% of the value of the control at the 52nd week. The region of interest (ROI) counts of damaged side on delayed bone imaging was obviously increased in comparison with control side at the 3rd week( P <0.01), there was no difference between both sides at the 6th week ( P >0.05), the ROI counts markedly decreased at the 12th week and very significantly declined at the 52nd week on irradiated side. Conclusions The study shows that the RBF increases and bone metabolism is activated at irradiated side in the earlier stage after irradiation, and both regional microcirculation and bone metabolism significantly decrease in the medium and late stage.