Abstract: Objective To establish a more stable and sustainable model of mouse lymphedema by adjusting the administrating timing and radiation doses. Methods Thirty-six female C57 mice aged 8weeks were randomly divided into 3 groups： ＂radiation before surgery＂ group （R＋S, n=12）, ＂radiation after surgery＂ group （S＋R, n=12）, and ＂radiation before and after surgery＂ group （r＋S＋r, n=12）. The experimental groups received radiation at varied time points： S＋R group, 4.5 Gy at 2 weeks after surgical treatment; R＋S group, 4.5 Gy at 3 days before surgery; and r＋S＋r group, 2.25 Gy at both 3 days before and 2 weeks after surgery. The volume change of the hind limbs of animals was measured by drainage method. Lymphangiogenesis in vivo situation was visualized by FDNG injection through the hind limb at 24th week after operation and immunohistochemistry staining was performed to show superficial lymphatic vessels. Results In six-month observation, all mice in the experimental groups formed lymphedema successfully. The r＋S＋r group showed the most stable hind limb lymphedema with lower mortality and morbidity rates. At 6 months post operation,according to the lymphatic mapping, the lymphatic vessels in R＋S and S＋R group increased, while rare lymphatic regeneration was observed in the r＋S＋r group. Immunohistochemistry revealed a decreased number of lymphatic vessels in the r＋S＋r group, compared with other groups （P〈0.05）. Conclusion A radiation dose of 2.25 Gy administered 3 days before surgery and 2 weeks after operation successfully enhanced the stability of the lymphedema model of mice hind limb.

Key words: Lymphedema, Animal model, Lymphatic vessels, Radiation