Essential Experimental Methods for Identifying Bonghan Systems as a Basis for Korean Medicine: Focusing on Visual Materials from Original Papers and Modern Outcomes

Figure 3

The internal Bonghan systems. (A) The Bonghan systems inside the heart stained by Trypan blue. Diagram from the third paper by the Bonghan research team (a), and photo images inside the bovine heart treating Trypan blue under a stereomicroscope by a modern research team (b and c). The Bonghan ducts (white arrows, a) and corpuscles (dotted circles) are indicated by the modern research team. SVC = superior vena cava; A = aorta; LA = left atrium; RA = right atrium; LPV = left pulmonary vein; RPA = right pulmonary artery; S = septum; LV = left ventricle; RV = right ventricle. The Bonghan corpuscles (black arrows, b) connected to the Bonghan ducts are stained blue, whereas the blood capillaries (red arrows, b) are not stained. The scale bar is 1 mm. The inset (c) demonstrates the lifting of a Bonghan duct using a needle showing the floating state of the Bonghan duct on the endocardium. The scale bar is 500 μm [20]. (B) The Bonghan duct in the lymphatic vessel without staining. The Bonghan duct (arrows) in the lymphatic vessel (dotted line) on the caudal vena cava of a rabbit under a stereomicroscope using halogen red light. The scale bar is 500 μm [21]. (C) The Bonghan duct in the lymphatic vessel stained by DiI. The Bonghan corpuscle (open arrow, a) and duct (arrows) in the lymphatic vessel (dotted line) on the caudal vena cava of a rabbit stained by DiI under a stereomicroscope. These are merges of bright-field and fluorescent images. A magnified view (b) shows that a Bonghan duct came out through the lymphatic vessel wall and entered the surrounding fat tissue (F). V is a valve weakly stained by DiI [21].