Rose Bengal Induced Photothrombosis in CAM Integrated Human Split Skin Grafts-A Feasibility Study

Wound healing is a complex process requiring an adequate supply of the wound area with oxygen and nutrients by neo-vascularization, to renew tissue. Local ischemia can result in the formation of chronic wounds. Since there is a lack of wound healing models for ischemic wounds, we aimed to develop a new one, based on chick chorioallantoic membrane (CAM) integrated split skin grafts and induction of ischemia with photo-activating Rose Bengal (RB) in a two-part study: (1) investigation of the thrombotic effect of photo-activated RB in CAM vessels and (2) investigation of the influence of photo-activated RB on CAM integrated human split skin xenografts. In both study phases, we observed a typical pattern of vessel changes after RB activation with a 120 W 525/50 nm green cold light lamp in the region of interest: intravascular haemostasis and a decrease in vessel diameter within 10 min of treatment. In total, the diameter of 24 blood vessels was measured before and after 10 min of illumination. Mean relative reduction of vessel diameter after treatment was 34.8% (12.3%-71.4%; p < 0.001). The results indicate that the present CAM wound healing model can reproduce chronic wounds without inflammation due to the statistically significant reduction of blood flow in the selected area using RB. Combined with xenografted human split skin grafts, we established the set up for a new chronic wound healing model for the research of regenerative processes following ischemic damage of the tissue.