The Flow Path of Alcian Blue From the Acupoint BL23 to the Surface of Abdominal Organs

Overall characteristic features of Alcian Blue (AB)-stained threadlike Bonghan ducts (BHDs) and corpuscles. BHDs are thin, semitransparent, and freely movable. A corpuscle (C) is linked to BHDs on opposite sides (arrows). Most of the BHDs stained partially or wholly by the AB solution. The thicknesses of the BHDs were about 50 μm, and those of corpuscles were about 400-500 μm.

Distribution of Alcian Blue (AB)-stained thread-like Bonghan ducts (BHDs) and corpuscles after AB injection at Urinary Bladder 23 (BL23). The AB-stained BHDs and corpuscles are mostly observed on the right sides of abdominal organs, including the right sides of the small intestine, the large intestine, the abdominal wall, the liver, and the stomach (dotted line: overall pathway; solid lines: individual pathways). The BHDs start from the liver or the great omentum of the stomach or duodenum and pass through the right abdomen. BHDs and corpuscles are mostly observed on the duodenum, the cecum, and the ascending and transverse colon.

Stereomicroscope image of Alcian Blue (AB)-stained threadlike Bonghan ducts (BHDs) and corpuscles on the transverse colon. Large (LC) and small (SC) corpuscles are linked by threadlike BHDs, and all parts of the BHDs are heavily stained by AB. The corpuscles are adhered to the surface of the intestine connected to the colon (Figures 4A,C) while the threadlike BHD is not adhered to the surface and moves freely (Figure 4B).

Stereomicroscope image of Alcian Blue (AB)- stained threadlike Bonghan ducts (BHDs) and a corpuscle on the surface of the right abdominal wall. The large corpuscle (LC) and the threadlike BHDs freely move and are heavily stained by AB. The size of the LC is about 1 mm, and the BHDs are about 30 μm.

Network of Alcian Blue (AB)-stained threadlike Bonghan ducts (BHDs) on the intestines. (A) Three AB-stained BHDs pass over the duodenum and are connected to each other. (B) BHDs form a network on the colon. These appear to be transparent on lower magnification. (C) Under higher magnification (rectangular part of B), these structures have some AB spots (closed arrows) and a bundled structure containing some subducts (open arrows).

Phase-contrast microscope image and nuclear staining using DAPI of an Alcian Blue (AB)-stained threadlike Bonghan duct (BHD). (A) Under a phase-contrast microscope, the threadlike BHD clearly reveals three subducts (dotted black arrow) and evidence of AB flowing (opened arrows) in the direction of the subducts. (B) Rod-shaped nuclei are observed on the BHD (arrows).

Transmission electron micrograph of a threadlike Bonghan duct (BHD). (A) The matrix of a threadlike BHD mainly consists of abundant bundles of collagen fibers (C), immune cells such as macrophages (MP) and flattened squamous like epithelial cells (Sq.E). (B) Higher magnification of rectangular area of A. Bundles of collagen fibers (C) and squamous-like epithelial cells (Sq.E) compose a subunit, and there are some collapsed sinuses and macrophages (MP) between individual subunits. (C) Higher magnification of the round area of A. A Sq.E, enveloped by collagen bundles (C), has some granules and many ribosome inside its cytoplasm. (D) The sinus between each subunit is surrounded by Sq.Es and their processes. There are some openings, about 2-3 μm, between the processes (arrows). (E, F) Higher magnification of the rectangular area. E and the round area F of B. Reticulofibers (R, dotted line) are revealed between the Sq.E and the bundle of collagen fibers. The nucleus (N) of the Sq.E consist of heterochromatin (H) and euchromatin (E) in about a 1:3 (H:E) ratio.