title: Ultrastructure of the Subcutaneous Primo-Vascular System in Rat Abdomen.
abstract: Recently, we identified the primo-vascular system (PVS), a novel vascular network, in rat subcutaneous tissues. Little is known about the subcutaneous PVS (sc-PVS). Here, we examined the ultrastructure of the sc-PVS in the hypodermis at the rat abdominal midline by electron microscopy. On the surface of sc-PVS, we observed three types of cells: microcells (5-6 μm), large elliptical cells (>20 μm), and erythrocyte (3-4 μm). The inside of the sc-PVS was filled with numerous cells, which can be classified into three major groups: leucocytes, mast cells, and erythrocytes. The dense leucocytes and mast cells were easily noticed. The extracellular matrix of the sc-PVS was mainly composed of extensive fibers (79 ± 6.5 nm) tightly covered by micro- (0.5-1 μm) and nanoparticles (10-100 nm). In conclusion, the ultrastructural features, such as the resident cells on and in the sc-PVS and fiber meshwork covered by particles, indicate that sc-PVS might act as a circulatory channel for the flow and delivery of numerous cells and particles. Our findings will help understand the nature of various sc-PVS beneath-the-skin layers and how they relate to acupuncture meridians.
authors.affiliation: Department of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, 151-742, Republic of Korea.
authors.forename: Chae Jeong
authors.initials: CJ
authors.lastname: Lim
authors.affiliation: Department of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, 151-742, Republic of Korea.
authors.forename: So Yeong
authors.initials: SY
authors.lastname: Lee
authors.affiliation: Department of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, 151-742, Republic of Korea. pdryu@snu.ac.kr.
authors.forename: Pan Dong
authors.initials: PD
authors.lastname: Ryu
mesh_terms: D000005:Abdomen; D015670:Acupuncture Therapy / Q000379:methods*; D000818:Animals; D001808:Blood Vessels / Q000166:cytology / Q000648:ultrastructure*; D004912:Erythrocytes / Q000648:ultrastructure; D005109:Extracellular Matrix / Q000648:ultrastructure; D007962:Leukocytes / Q000648:ultrastructure; D008297:Male; D008407:Mast Cells / Q000648:ultrastructure; D016740:Meridians; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles; D017207:Rats, Sprague-Dawley; D040521:Subcutaneous Tissue / Q000098:blood supply*
keywords: Electron microscopy; Fibrous structure; Primo-vascular system (PVS); Resident cells; Subcutaneous PVS