Quantitative analysis of IR-induced effects on locomotion in

Suzuki, Michiyo; Sakashita, Tetsuya; Tsuji, Toshio*; Hattori, Yuya; Kobayashi, Yasuhiko

We have examined the effects of ionizing radiation (IR) on locomotion in using "body bends" (the number of bends in the anterior body region) and reported an IR-induced reduction in motility. However, the degree of motility in each region of the body has not been established. In the present study, we employed a video-based analysis and investigated the IR-induced effects on locomotion in more detail. were irradiated with graded single doses (0-1.5 kGy) of Co -rays. After irradiation, animals were transferred to a plate, either with or without food. The movements of animals were video-recorded. The video images were analyzed off-line. Briefly, the body line was skeletonized and evenly divided into 12 segments; X- and Y-coordinates of each point on the body were subsequently acquired. To evaluate the motility of each point on the body, the moving distance of each of 13 points over a 5 s period was calculated using the X- and Y-coordinates. In addition, we introduced a novel standard, namely the straight distance from head to tail, to evaluate the body form. Under both the -food and +food conditions, the moving distance of irradiated animals was reduced in a dose-dependent manner at each point on the body, and there was no difference between the effects on each region of the body. Furthermore, we evaluated body form and found that IR-induced quantitative changes in body form.