V5与兔放射性肺损伤发生相关性的实验研究

Experiment research of correlation between v5 and rabbit radiation-induced lung injury

目的建立放射性肺损伤兔动物模型,通过限定不同V5值,测定肺组织中肿瘤坏死因子α(TNF-α)、转化生长因子β1(TGF-β1)的表达情况,考察其与放射性肺损伤发生的相关性。方法健康新西兰种大白兔30只,实验组25只,共5组,每组5只,分别设定V5 40%、50%、60%、70%、80%,对照组5只,假性照射,每只均进行CT模拟、靶区勾画、计划制作并进行照射,6 MV能量射线,3野调强适形放疗(IMRT),等中心照射,全肺剂量30 Gy/3F。观察至8周后解剖,分别进行HE染色、TGF-β1、TNF-α的检测。结果病理染色提示自V5 50%开始出现放射性肺炎病理学改变。所有实验组TGF-β1、TNF-α较对照组表达增强,且与V5正相关。TGF-β1表达情况:V5 40%组与70%、80%组有统计学差异(P<0.05),但与50%、60%及对照组无统计学差异;除V5 40%外,所有实验组均与对照组有统计学差异(P<0.05)。TNF-α表达情况:V5 80%与70%和对照组有统计学差异,其余各组两两间均无统计学差异。结论当V5控制在40%时可减少放射性肺损伤的发生,预测放射性肺损伤发生的V5"门槛值"在50%附近。

Objective To establish the rabbit model of radiation-induced lung injury for the study of its relationship with V5 by measuring TNF-α and TGF-β1 content. Methods Thirty New Zealand rabbits were randomly divided into six groups, every eight in V5 40%, 50%, 60%, 70%, 80%and control group. Each rabbit received CT scan, delineation of target region and went on radiation with DT 30Gy/3F by three-yield IMRT. All rabbits were sacrificed at 8 week after irradiation. The pathological changes were observed with light microscopies and the expression of TNF-α and TGF-β1 in local lung tissue were detected by immunohistochemistry. Results The expression of TNF-αand TGF-β1 enhanced in each experimental group than control group. High expression were detected in higher V5 percentage group. The expression of TGF-β1： V5 40% showed significantly different with 70%, 80%, respectively （P〈0.05）. But no differences were found by comparing with V5 50%, 60%and control group. All but V5 40%group was statistically different with control group （P〈0.05）. The expression of TNF-α：Only V5 70%and control group was statistically different related to V5 80%（P〈0.05）. Conclusion When V5 is set by 40%, it could reduce the occurrence of radiation-induced lung injury,and the threshold of predicting radiation-induced lung injury could be near 50%.