转TGF-β1基因小鼠体内放疗敏感性初步评价

In vivo experiment of radiosensitivity of TGF-β1 in transgenic mouse

目的:针对颌骨放射性骨坏死的最新机制—放射诱导纤维萎缩机制,设计转TGF-β1基因小鼠与普通野生型小鼠的放疗实验,验证转基因小鼠的体内放疗敏感性。方法:以转TGF-β1基因小鼠和普通野生型C57BL/6J小鼠为实验动物,以16Gy为照射剂量,采用4MV直线加速器对小鼠左侧股骨进行单次照射,临床病理学检测放射辐照侧与非辐照侧股骨骨钙蛋白(OCN)、平滑肌肌动蛋白(SMA)及TGF-β1的表达,采用SAS6.0软件包对数据进行统计学处理,并对股骨及周围软组织行Masson染色,检测组织纤维化的程度。结果:放射辐照后6周,股骨病理切片HE染色显示,转基因小鼠辐照侧股骨骨细胞缺失程度(15.31%±7.96%)较野生型小鼠(3.69%±3.69%)严重;Masson染色未见明显的纤维化证据,但SMA免疫组化结果显示转基因小鼠SMA阳性细胞比例较野生型小鼠高;骨损伤指标OCN免疫组化阳性细胞比例转基因小鼠较野生型小鼠低,差异均具有显著性。结论:转基因小鼠放射辐照后,其骨损伤程度与骨纤维化的指标均比野生型小鼠高,提示TGF-β1能提高组织对放射线的敏感性。

PURPOSE： This study focused on the radiation-induced fibroatrophic process （RIF） and designed irradiation experiment of TGF-β1 transgenic and wild type mice to verify the radiosensitivity of transgenic mouse. METHODS： Transgenic mice and wild type mice underwent radiotherapy of 16Gy at the site of left femur by 4MV linear accelerator. Femur and surrounding soft tissues were examined by Masson staining; expression changes of osteocalcin, smooth muscle actin and TGF-β1 in femur were examined by immunohistochemistry and the data was analyzed with SAS6.0 software package to evaluate the radiological sensitivity of transgenic mice compared with wild type mice. RESULTS： Six weeks after irradiation, the osteocytes loss in irradiated legs of transgenic mice （15.31%±7.96%） was more serious than that in irradiated legs of wild type mice （3.69%±3.69%）. There was no obvious evidence for fibrosis in Masson staining of soft and hard tissue. In immunohistochemical analysis, the labeling index of SMA and OCN showed significant difference between transgenic mice and wild type mice. CONCLUSION： Significant difference in indexes of bone injury and fibrogenesis between transgenic mice and wild type mice after irradiation showed higher radiosensitivity in TGF-β1 transgenic mice.