Visualizing spatiotemporal pattern of vascularization by SWIR fluorescence imaging in a mouse model of perforator flap transplantation

Abstract Vascularization as a spatiotemporally interlaced process involving angiogenesis and vascular remodeling, has seldom been investigated comprehensively regarding the interrelationship of the two intertwining but sequential processes. Here, a shortwave infrared (SWIR) fluorescence imaging strategy with quantum dots (QDs) is designed to dynamically visualize vascularization in vivo and in situ in a perforator transplantation mouse model. The vascularization process could be directly perceived from the established flap model with an optimal observation window at 10 min post-injection. Based on SWIR technology and image processing, it was revealed that temporally, angiogenesis lasted throughout 21 days after surgery while vascular remodeling took a dominant role after 14 days both in vivo and in situ. Moreover, four perforasomes of the flap in situ displayed spatially that Zone IV shortened the vascularization process with sufficient blood supply from the LDCIA, while Zone II recovered slowly from ischemia with a lack of blood supply owing to choke zone theory. This study pioneered to add novel cognition of spatiotemporal pattern of vascularization through visualizing angiogenesis and vascular remodeling simultaneously and dynamically, thus facilitating further investigation into the mechanisms behind vascularization.