Law M P, Thomlinson R H
Br J Radiol. 1978 Nov;51(611):895-904. doi: 10.1259/0007-1285-51-611-895.
Late fibrosis in normal tissue is a complication which develops gradually after radiotherapy. It may be related to increase in vascular permeability induced by radiation. Plasma proteins leak into irradiated tissue where fibrinogen may be converted into fibrin which is gradually replaced by fibrous tissue. Vascular changes in the rat ear were investigated for six months after X-irradiation; Blood volume and vascular permeability were measured in vivo by monitoring the radioactivity in both irradiated and control ears after intravenous injection of phosphorus 32 labelled red cells and either iodinated (iodine 125) albumin or fibrinogen. After a single dose of 40 Gy there was an early increase in vascular permeability to both albumin and fibrinogen. After 20 Gy permeability to albumin was only increased during desquamation but extra-vascular fibrinogen accumulated at earlier times. Extravascular albumin was removed rapidly from irradiated ears, whereas some residual fibrinogen remained. Vascular permeability returned to normal but six weeks and showed no further changes up to six months after irradiation. Differences between the accumulation of extravascular albumin and fibrinogen at early times after irradiation could be due to some fibrinogen being fixed in the tissue. However, the rat ear showed no late changes comparable to the gradual development of late fibrosis seen in man.
正常组织中的晚期纤维化是放疗后逐渐出现的一种并发症。它可能与辐射诱导的血管通透性增加有关。血浆蛋白渗漏到受照射组织中，在那里纤维蛋白原可能转化为纤维蛋白，后者逐渐被纤维组织取代。对大鼠耳朵进行X射线照射后六个月，观察其血管变化；静脉注射磷32标记的红细胞以及碘化（碘125）白蛋白或纤维蛋白原后，通过监测受照射耳朵和对照耳朵中的放射性，在体内测量血容量和血管通透性。单次给予40 Gy剂量后，血管对白蛋白和纤维蛋白原的通透性早期均增加。给予20 Gy剂量后，白蛋白通透性仅在脱屑期间增加，但血管外纤维蛋白原在更早的时候就开始积聚。血管外白蛋白从受照射耳朵中迅速清除，而一些残留的纤维蛋白原仍留存。血管通透性在六周时恢复正常，照射后六个月内未显示进一步变化。照射后早期血管外白蛋白和纤维蛋白原积聚的差异可能是由于一些纤维蛋白原固定在组织中。然而，大鼠耳朵未出现与人类中晚期纤维化逐渐发展相当的晚期变化。
