Evaluation of Vascular Permeability in Inflamed Vessels of the Cremaster Muscle in Live Mice

Inflammation in vascular structures due to external factors such as injury or infection inevitably leads to blood leakage. Therefore, measuring blood infiltrated into tissue may serve as an indication for the extent of an inflammatory reaction or injury. There are various methods of confirming vascular permeability in vivo and in vitro; for example, using a blood vessel permeable dye, the dye efflux can be quantitatively measured with a spectrophotometer. Although the aforementioned commonly used methods can measure leaked dye without difficulty, substantial limitations exist regarding the time points of blood leakage that can be measured. Here, we describe the details of a novel protocol to identify and analyze the real-time progression of blood leakage in vivo. This method, by combining existing methods with real-time imaging, is expected to immensely improve the visualization and evaluation of vascular permeability.