Establishment of acute radiation proctitis model in rats

HU Tingting; CAI Hongyi.

doi:10.3969/j.issn.1009-0460.2019.07.002

Abstract：Objective To investigate an method to establish rat models of acute radiation proctitis. Methods A total of 50 male Wistar rats were divided into 5 groups, with 10 rats in each group, and irradiated by single pelvic local irradiation with linear ac?celerator. The radiation doses were 16. 5, 19, 21. 5 and 24Gy, respectively, and blank control group was set. After irradiation, the in?take and drinking water, body mass, defecation and autonomous activity of rats in each group were observed. The pathological changes of rectal tissues were observed under light microscope. Results Rats in 0 Gy group had normal food intake, water intake and autono?mous activities, and their body mass increased. The rats in 16. 5Gy group had no significant decrease in food and water intake. Sparse stool appeared in some rats. The pathological sections showed local mucosal destruction and local inflammatory cell infiltration. The clinical observation score was 2. 33±0. 42, and the pathological score was 1. 40±0. 52. After 19 and 21. 5 Gy irradiation, the intake of water decreased, and the rats became thin. Loose stool and mucous stool appeared. Under the light microscope, the rectal mucosa was slightly detached, and the outline of the lamina propria was incomplete with disordered structure. The clinial observation scores were 3. 13±0. 42 and 3. 40±0. 32, and the pathological scores were 2. 60±0. 52 to 3. 40±0. 51, respectively. In 24Gy group, the intake of food and water decreased significantly, and bloody stools and mucus appeared.Most glandular defects could be seen in pathological sec?tions. The clinical observation score was 3. 71±0. 28, and the pathological score was 3. 70±0. 48. From the 4th day after radiation, the body mass in 0 Gy group was higher than other groups (P＜0. 05). The clinical observation score and the pathological score were lower in 16. 5 Gy group compared with 19, 21. 5 and 24 Gy groups ( P＜0. 05). Conclusion The dose of single pelvic local irradiation by linear accelerator is 19?21. 5Gy, which can induce acute radiation proctitis in rats. The model can accurately reflect the clinical and pathological features of radiation enteritis and can be used for experimental research.