Establishment of irradiation wound model in adult Bama miniature pigs

Abstract

Objective To establish experimental radioactive wound model in miniature pig and observe its pathological changes in order to carry out in vivo study of radioactive wound-related diseases. Methods According to the random number table, eight adult Bama miniature pigs were divided into four groups after being anesthetized: normal control and experiment groups exposed to 0, 10, 20 and 30 Gy respectively using the X-ray linear accelerator. Then a puncher was use to prepare full-thickness skin defects (4 cm in length) in the irradiation site. Wound samples were collected every other week to observe wound healing. RT-PCR was used to measure expressions of tumor necrosis factor (TNF)-α and transforming growth factor (TGF)-β in wound tissues 35 days after irradiation. At the same time, Western blot was utilized to detect expressions of CD31 and collagen Ⅰ. HE staining was applied to observe histopathological changes of the radioactive wound. Results Skin wounds in normal control group healed in 35 days. Whereas in 20 and 30 Gy experiment groups, the wounds were not healed in 63 days and the healing rate was gradually weakened with the irradiation dose increasing. Expression ratio of TNF-α mRNA was 0.315±0.007 in normal control group, 0.984±0.211 in 10 Gy experiment group, 1.140±0.088 in 20 Gy experiment group, and 0.471±0.030 in 30 Gy experiment group. Expression ratio of TGF-β mRNA was 0.402±0.018 in normal control group, 1.707±0.147 in 10 Gy experiment group, 1.933±0.078 in 20 Gy experiment group, and 0.968±0.084 in 30 Gy experiment group. Expressions of TNF-α and TGF-β mRNA were significantly increased in 20 Gy experiment group compared to normal control group (P<0.05). Expressions of CD 31 and Collagen Ⅰ protein were inhibited in 20 Gy experiment group compared to normal control group (P<0.05). Epithelialization and granulation tissue regeneration in 20 Gy experiment group were impaired. Conclusion An irradiation wound model in Bama miniature pigs can be efficiently and effectively simulated using the 20 Gy X-ray irradiation combined with full-thickness skin defect, and can be used to study the pathophysiology and therapeutic intervention of radioactive wound-related diseases in vivo. Key words: Radiation injuries, experimental; Ulcer; Models, animal