Establishment of a standardized rat model of chronic radiation proctitis and preliminary evaluation of its association with tubulin

Figure 1 Irradiation setup showing rat fixation and shielding. A and B: The yellow rectangle indicates the irradiation area, while the red area represents the rectal region after tissue shielding.

Figure 2 Effects of different radiation doses on rats. A: Survival curve; B: Endoscopic appearance of rat rectum at 2 weeks post-irradiation across different dose groups; C: Dose-endoscopic score curve; D: Hematoxylin-eosin and Masson staining of rectal tissues at 3 months (scale bar = 200 µm); E: Dose-Radiation Injury Score curve. HE: Hematoxylin-eosin.

Figure 3 Immunofluorescence staining for vascular endothelial growth factor in rat rectum at 2 weeks and 3 months post-irradiation. VEGF: Vascular endothelial growth factor.

Figure 4 Endoscopic time-course changes in rats exposed to different radiation doses. A: Sequential endoscopic findings in the 15 Gy group; B: Sequential endoscopic findings in the 25 Gy group; C: Sequential endoscopic findings in the 35 Gy group; D: Time-endoscopic score curves for 15 Gy, 25 Gy, and 35 Gy groups.

Figure 5 High-dose irradiation induces significant degradation of cytoskeletal proteins in rat rectal tissues. A: Representative Western blot images of the cytoskeletal components α-tubulin and β-actin in rectal tissues at 2 weeks post-irradiation across different dose groups (15-35 Gy). Histone H3 was utilized as an internal loading control to represent total nuclear protein and confirm equal cell equivalent loading per lane, demonstrating stable expression across all doses; B and C: Quantitative densitometric analysis of relative α-tubulin (B) and β-actin (C) protein levels, normalized to histone H3. The data indicate a severe, dose-dependent loss of cytoskeletal integrity starting at 20 Gy. Data are presented as mean ± SD. ^aP < 0.05 compared to the 15 Gy group; ^bP < 0.0001 compared to the 15 Gy group. NS: Not significant.