基于小动物精准放疗平台构建Wistar大鼠急性放射性食管炎动物模型

目的 基于小动物精准放疗平台(SARRP)建立Wistar大鼠急性放射性食管炎体内模型。方法 将36只Wistar大鼠按照随机数表法分为对照组、40、60和75 Gy组,每组9只。基于SARRP结合照射前磁共振图像(MRI)勾画大鼠食管靶区并制定计划,每次分别照射0、8、12和15 Gy,连续照射5 d,观察大鼠体重、进食量、食管病理和磁共振图像改变。结果 75 Gy组大鼠在照后第6天体重最先出现明显降低(P<0.05),照后第9天各照射组大鼠食管较对照组增粗(F=14.20,P<0.05)。照后第9天HE染色显示,40 Gy组放射性食管炎形成率为4/5,60 Gy 组食管炎形成率为5/5,且以轻度食管炎为主,75 Gy组食管炎形成率为5/5,其中3/5表现为重度。照后第9天各组大鼠病理损伤评分M(Q₁, Q₃)]为0、1.0(0.5, 2.5)、1.0(1.0, 2.5)和4.0(1.5, 6.0),75 Gy组与对照组相比,差异有统计学意义(H=12.69,P<0.05)。动态监测颈部MRI图像后发现,照后第9天时各照射组大鼠食管信号增强变宽。结论 本实验基于小动物精准放疗平台结合MRI成功建立大鼠的急性放射性食管炎动物模型,75 Gy是最佳照射剂量,且第9天是最佳观察时间点。

Establishment of acute radiation-induced esophagitis model of Wistar rats based on a small animal precision radiotherapy platform

Objective To establish an in vivo model of acute radiation esophagitis in Wistar rats based on a small animal precision radiotherapy platform (SARRP). Methods Thirty-six Wistar rats were randomly divided into control group, 40, 60 and 75 Gy groups. Based on MRI images, the esophageal target area of rats was outlined and the radiotherapy plan was formulated. The rats were respectively irradiated with 0, 8, 12 and 15 Gy per day for 5 consecutive days. The changes of body weight, food intake, esophageal pathology and magnetic resonance imaging were observed. Results The body weight of rats in 75 Gy group decreased significantly on the 6th day after irradiation (IR) (P<0.05). The esophageal tissue of rats in each IR group was thicker than that in control (F = 14.20, P < 0.05). HE staining showed that the formation rate of radiation-induced esophagitis in 40 Gy and 60 Gy groups were 4/5 and 5/5, respectively, mainly mild. In 75 Gy group, the incidence of radiation-induced esophagitis approached to 5/5, of which 3/5 was severe at 9 d post-IR. The pathological injury scores M(Q₁, Q₃)] of rats in each group were 0, 1.0 (0.5, 2.5), 1.0 (1.0, 2.5) and 4.0 (1.5, 6.0) on the 9th day after IR. There was significant difference between the 75 Gy group and the control group (H=12.69, P<0.05). After dynamic monitoring of neck MRI images, it was found that the esophageal signal of rats in each IR group increased and widened at 9 d post-irradiation. Conclusions The animal model of acute radiation-induced esophagitis in rats was successfully established based on a small animal precision radiotherapy platform combined with MRI. 75 Gy was the best irradiation dose and the 9th day was the best observation time point.