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Evidence-Based Complementary and Alternative Medicine
Volume 2013 (2013), Article ID 350815, 12 pages
Research Article

Gross Morphological Features of the Organ Surface Primo-Vascular System Revealed by Hemacolor Staining

1Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151-742, Republic of Korea
2Laboratory Animal Research Center, College of Pharmacy, Hanyang University, Ansan 426-791, Republic of Korea
3Laboratory of Clinical Pathology, College of Veterinary Medicine, Seoul National University, Seoul 151-742, Republic of Korea

Received 11 February 2013; Revised 30 June 2013; Accepted 2 July 2013

Academic Editor: Walter J. Akers

Copyright © 2013 Chae Jeong Lim et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The primo-vascular system (PVS), which consists of primo-vessels (PVs) and primo-nodes (PNs), is a novel thread-like structure identified in many animal species. Various observational methods have been used to clarify its anatomical properties. Here, we used Hemacolor staining to examine the gross morphology of organ-surface PVS in rats. We observed a sinus structure (20–50 μm) with a remarkably low cellularity within PNs and PVs and several lines of ductules (3–5 μm) filled with single cells or granules (~1 μm) in PV. Both sinuses and ductules were linearly aligned along the longitudinal axis of the PVS. Such morphology of the PVS was further confirmed by acridine orange staining. In PN slices, there was a honeycomb-like structure containing the granules with pentagonal lumens (~10 μm). Both PVs and PNs were densely filled with WBCs, RBCs, and putative mast cells (MCs), which were 90.3%, 5.9%, and 3.8% of the cell population, respectively. Granules in putative MCs showed spontaneous vibrating movements. In conclusion, the results show that Hemacolor, a simple and rapid staining system, can reveal the gross morphological features reported previously. Our findings may help to elucidate the structure and function of the PVS in normal and disease states in future studies.