Effect of age on thrombosis and morbidity in the mouse-limb transplantation model

Murine models of limb transplantation have been recently described. Because of the technical challenge, non-technical factors that influence the success rate and are easily controlled should be considered. This study investigated the effect of recipient animal age on anastomotic thrombosis, morbidity, and mortality. Twelve allogeneic heterotopic hindlimb transplants were performed using the femoral vessels with end-to-end arterial and end-to-side venous anastomoses. Group 1 (n=8) consisted of 2 to 3-month-old mice weighing 17 to 20 g, and Group 2 (n=7) included 7 to 8-month-old mice weighing 24 to 27 g. In Group 1, 6/8 (75 percent) transplants were successful, while in Group 2, only 1/7 (14 percent) allografts survived (p<0.05). A statistically significant difference in the incidence of vascular compromise of the ipsilateral recipient hindlimb was also noted (p<0.01). The authors conclude that although smaller, juvenile, inbred mice have a higher anastomotic patency rate, with greater collateral vasculature in the hindlimbs, and are therefore more suitable for limb transplantation research.