不同剂量单次照射下大鼠急性放射性心脏损伤模型的构建与评价

Construction and evaluation of acute radiation heart injury rat model treated with different dosage and single irradiation

目的评估不同剂量单次照射构建大鼠放射性心脏损伤模型的科学性、合理性、可行性。方法 40只SD雄性大鼠随机分为正常、5 Gy、10 Gy、20 Gy、30 Gy组。直线加速器下照射大鼠心脏,剂量率为600 c Gy/min,源皮距为100cm,照射野2.0 cm×2.0 cm。照射后1周末和4周末,各组分别随机取4只大鼠,经右颈总动脉插管,测量血流动力学指标,后检测大鼠血清中心肌肌钙蛋白Ⅰ(cTnⅠ)含量,以及超氧化物歧化酶(SOD)和丙二醛(MDA)活性;取心尖部组织行HE、Masson染色。结果照射后1周,心脏血流动力学参数变化不明显,而cTnⅠ、SOD、MDA指标差异明显(P<0.05)。照射后4周,5 Gy、10 Gy组心功能参数较正常组无明显变化,20 Gy和30 Gy组心功能指标变化明显(P<0.05),但两组间差别不大,cTnⅠ、SOD、MDA指标与正常组比较差异有统计学意义(P<0.05)。HE染色结果显示,4周末各剂量照射组有不同程度的病理学形态改变,Masson结果显示心肌间质和小血管周围有不同程度胶原纤维沉积改变。结论在构建大鼠急性放射性心脏损伤模型时,不同剂量照射有其各自的特征。大鼠心脏在20 Gy单次剂量照射后,可较好观察到急性放射性心脏损伤的变化。氧化应激在RIHD的发生、发展中扮演重要角色。

Objective To evaluate the rationality,scientific and feasibility of acute radiation-induced heart disease caused by different single doses radiation in rats. Methods Forty SD male rats were randomly divided into normal,5 Gy,10 Gy,20 Gy and 30 Gy groups. The rats were irradiated under the linear accelerator at heart,the dose rate： 600 c Gy/min,the source skin distance： 100 cm,the radiation field： 2. 0 cm × 2. 0 cm. At the end of 1 week and 4 weeks after irradiation,4 rats were randomly selected from each group and were intubated with the right common carotid artery to measure hemodynamic parameters. And the data of hemodynamic indicators were examined through biological function experiment system. The content of cardiac troponin I（ c Tn I）,the content of malondialdehyde（ MDA） and the activity of super oxide dismutase（ SOD） was tested. Apical tissues were stained with HE and Masson. Results After 1 week of irradiated,there was no obvious change of cardiac hemodynamic parameters,while the indexes of c Tn I,SOD and MDA were significantly different（ P〈0.05）. After 4 weeks of irradiated,the cardiac function parameters in 5 Gy and 10 Gy group had no significant changes compared with those in normal group,while the heart function in 20 Gy and 30 Gy group was significantly impaired（ P〈0.05）,but the difference of SOD and MDA between the two groups was statistically significant（ P〈0.05）. The results of HE staining showed that different degrees pathological changes were observed in each irradiated groups after 4 week. Masson＇s results showed that there were changes of collagen deposition in the myocardium and small vessels. Conclusion In constructing acute radiation-induced cardiac injury in rats,different doses of irradiation have their different characteristics. After exposure to a single dose of 20 Gy in rat hearts,changes in acute radiation-induced cardiac injury are better observed. Oxidative stress plays an important role in the occurrence and development of RIHD.