Alcian blue staining method for visualizing bonghan ducts inside blood vessels of mice

In modern anatomy, there are no threadlike structures floating inside blood vessels without adhering to the vessel wall. However recently we found novel threadlike tissues that are called intravascular Bonghan ducts (IBHD) inside blood vessels of mice using Alcian blue (AB) staining method. These novel structures were introduced in Bonghan theory as a part of meridian system in 1960’s. For in vivo imaging of IBHD, AB solution (pH 7.4) that can easily stain mucopolysaccharides like hyaluronic acid was used. After injecting AB solution into the femoral vein of a mouse we found the threadlike structures stained deep blue inside inferior vena cava. Using this method, we got the anatomical data such as diameter of threadlike structures. Also we report on the histological results such as hematoxylin, eosin and AB staining to show the composition of cells and extracellular matrix in the IBHD. Further studies are needed to develop specific imaging method of IBHD and to investigate their physiological functions especially in relation with other circulatory systems.