Variability in endogenous perfusion recovery of immunocompromised mouse models of limb ischemia

Immunocompromised hind limb ischemia (HLI) murine models are essential for preclinical evaluation of human cell-based therapy or biomaterial-based interventions. These models are used to generate proof of principle that the approach is effective and also regulatory preclinical data required for translation to the clinic. However, surgical variations in creation of HLI models reported in the literature introduce variability in the pathological manifestation of the model, in consequence affecting therapeutic endpoints. This study aims to compare the extent of vascular regeneration in HLI-induced immunocompromised murine models to obtain a stable and more reproducible injury model for testing. Athymic and Balb/C nude mice underwent HLI surgery with single and double ligation of femoral artery (FA). The recovery from surgery was observed over a period of 2 weeks with respect to ischemia reperfusion using laser Doppler and clinical signs of necrosis and ambulatory impairment. Double ligation of the FA results in a more severe response to ischemia in Balb/C with endogenous perfusion recovery up to 50% ± 10% compared with 75% ± 20% in athymic nude mice. Single iliac artery (IA) and FA lead to creation of mild ischemia compared with femoral artery-vein (FAV) pair ligation in Balb/C. Microcirculatory parameters indicate significantly lower capillary numbers (26 ± 3/mm²) and functional capillary density (203 ± 5 cm/cm²) in the FAV group. In this study, we demonstrate a reproducible, arterial double ligation in an immunocompromised Balb/C nude mouse model that exhibits characteristic pathological signs of ischemia with impaired endogenous recovery.