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Identification of Primo-Vascular System in Abdominal Subcutaneous Tissue Layer of Rats.

Lim CJ, Lee SY, Ryu PD - Evid Based Complement Alternat Med (2015)

Bottom Line: The distribution pattern of nodes and vessels in the scPVS closely resembled that of the conception vessel meridian and its acupoints.In conclusion, our results newly revealed that the PVS is present in the abdominal subcutaneous tissue layer and indicate that the scPVS tissues are closely correlated with acupuncture meridians.Our findings will help to characterize the PVS in the other superficial tissues and its physiological roles.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151-742, Republic of Korea.

ABSTRACT
The primo-vascular system (PVS) is a novel network identified in various animal tissues. However, the PVS in subcutaneous tissue has not been well identified. Here, we examined the putative PVS on the surface of abdominal subcutaneous tissue in rats. Hemacolor staining revealed dark blue threadlike structures consisting of nodes and vessels, which were frequently observed bundled with blood vessels. The structure was filled with various immune cells including mast cells and WBCs. In the structure, there were inner spaces (20-60 µm) with low cellularity. Electron microscopy revealed a bundle structure and typical cytology common with the well-established organ surface PVS, which were different from those of the lymphatic vessel. Among several subcutaneous (sc) PVS tissues identified on the rat abdominal space, the most outstanding was the scPVS aligned along the ventral midline. The distribution pattern of nodes and vessels in the scPVS closely resembled that of the conception vessel meridian and its acupoints. In conclusion, our results newly revealed that the PVS is present in the abdominal subcutaneous tissue layer and indicate that the scPVS tissues are closely correlated with acupuncture meridians. Our findings will help to characterize the PVS in the other superficial tissues and its physiological roles.

No MeSH data available.


Hemacolor staining of the threadlike structure isolated from the rat abdominal subcutaneous tissue. (a) Threadlike structure isolated from the Hemacolor-stained layer of the subcutaneous tissue. (b) Typical longitudinal image of a whole threadlike structure (marked as “b” in (a)). ((c) and (d)) Two major types of cells in the threadlike structure: large granular (arrows) or small round cells (arrowheads). Note that the cells in the node (c) and in the vessel (d) are aligned differently. (e) Toluidine blue staining of the large granular cells (arrows).
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fig5: Hemacolor staining of the threadlike structure isolated from the rat abdominal subcutaneous tissue. (a) Threadlike structure isolated from the Hemacolor-stained layer of the subcutaneous tissue. (b) Typical longitudinal image of a whole threadlike structure (marked as “b” in (a)). ((c) and (d)) Two major types of cells in the threadlike structure: large granular (arrows) or small round cells (arrowheads). Note that the cells in the node (c) and in the vessel (d) are aligned differently. (e) Toluidine blue staining of the large granular cells (arrows).

Mentions: The threadlike structure was isolated and the tissue was restained in vitro to identify the cellular properties of the threadlike structure stained by Hemacolor. Figure 5(a) shows a sample on the slide glass of a threadlike structure composed of nodes and vessels connected by these nodes. Figure 5(b) is a representative stereoscopic image of the threadlike structure stained by Hemacolor. The Hemacolor-stained cells of the threadlike structure were mainly classified into two groups based on their morphologies: small round cells (~10 μm) and large granular cells (10–20 μm). The cells in the vessels and nodes differed in shape and distribution. The cells within a node were mostly round in shape and were dispersed unsystematically (Figure 5(c)). In contrast, the cells within a vessel were elliptical and linearly aligned along the longitudinal axis of the vessel (Figure 5(d)). Figure 5(e) shows the image of the cells of the threadlike structure revealed by toluidine blue staining, which is widely used to stain selectively MCs [20]. In previous studies, the PVS has been found to contain a variety of immune cells, including MCs and WBCs [6, 17]; therefore, in this study, toluidine blue staining was performed. The granules within large granular cells showed the typical metachromatic staining property of toluidine blue staining, indicating that the large granular cells in the threadlike structure were MCs (Figure 5(e)) [20]. The threadlike structure was also stained with acridine orange staining to determine DNA (revealed green) and RNA (revealed red) components for the further characterization of the cellular properties of the threadlike structure [19]. Figure 6(a) illustrates the threadlike structure consisting of one node and connecting vessel stained with acridine orange. The majority of cells in the threadlike structure were stained a green color, as shown in Figure 6. The nuclei of the small round cells were stained green (Figures 6(b) and 6(c), arrowheads), whereas the large granular cells were stained green and red in the nuclei and surrounding granules, respectively (Figures 6(b) and 6(c), arrows). The shape and distribution of the acridine orange-stained cells were similar to those of the Hemacolor staining, as shown in Figure 5. Most cells in the vessel were aligned along the long axis of the vessel (Figures 6(a), arrowheads in the bottom inset, and 6(c)). In contrast, the cells in the node were randomly distributed without any clear direction (Figure 6(b)).


Identification of Primo-Vascular System in Abdominal Subcutaneous Tissue Layer of Rats.

Lim CJ, Lee SY, Ryu PD - Evid Based Complement Alternat Med (2015)

Hemacolor staining of the threadlike structure isolated from the rat abdominal subcutaneous tissue. (a) Threadlike structure isolated from the Hemacolor-stained layer of the subcutaneous tissue. (b) Typical longitudinal image of a whole threadlike structure (marked as “b” in (a)). ((c) and (d)) Two major types of cells in the threadlike structure: large granular (arrows) or small round cells (arrowheads). Note that the cells in the node (c) and in the vessel (d) are aligned differently. (e) Toluidine blue staining of the large granular cells (arrows).
© Copyright Policy - open-access
Related In: Results  -  Collection

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fig5: Hemacolor staining of the threadlike structure isolated from the rat abdominal subcutaneous tissue. (a) Threadlike structure isolated from the Hemacolor-stained layer of the subcutaneous tissue. (b) Typical longitudinal image of a whole threadlike structure (marked as “b” in (a)). ((c) and (d)) Two major types of cells in the threadlike structure: large granular (arrows) or small round cells (arrowheads). Note that the cells in the node (c) and in the vessel (d) are aligned differently. (e) Toluidine blue staining of the large granular cells (arrows).
Mentions: The threadlike structure was isolated and the tissue was restained in vitro to identify the cellular properties of the threadlike structure stained by Hemacolor. Figure 5(a) shows a sample on the slide glass of a threadlike structure composed of nodes and vessels connected by these nodes. Figure 5(b) is a representative stereoscopic image of the threadlike structure stained by Hemacolor. The Hemacolor-stained cells of the threadlike structure were mainly classified into two groups based on their morphologies: small round cells (~10 μm) and large granular cells (10–20 μm). The cells in the vessels and nodes differed in shape and distribution. The cells within a node were mostly round in shape and were dispersed unsystematically (Figure 5(c)). In contrast, the cells within a vessel were elliptical and linearly aligned along the longitudinal axis of the vessel (Figure 5(d)). Figure 5(e) shows the image of the cells of the threadlike structure revealed by toluidine blue staining, which is widely used to stain selectively MCs [20]. In previous studies, the PVS has been found to contain a variety of immune cells, including MCs and WBCs [6, 17]; therefore, in this study, toluidine blue staining was performed. The granules within large granular cells showed the typical metachromatic staining property of toluidine blue staining, indicating that the large granular cells in the threadlike structure were MCs (Figure 5(e)) [20]. The threadlike structure was also stained with acridine orange staining to determine DNA (revealed green) and RNA (revealed red) components for the further characterization of the cellular properties of the threadlike structure [19]. Figure 6(a) illustrates the threadlike structure consisting of one node and connecting vessel stained with acridine orange. The majority of cells in the threadlike structure were stained a green color, as shown in Figure 6. The nuclei of the small round cells were stained green (Figures 6(b) and 6(c), arrowheads), whereas the large granular cells were stained green and red in the nuclei and surrounding granules, respectively (Figures 6(b) and 6(c), arrows). The shape and distribution of the acridine orange-stained cells were similar to those of the Hemacolor staining, as shown in Figure 5. Most cells in the vessel were aligned along the long axis of the vessel (Figures 6(a), arrowheads in the bottom inset, and 6(c)). In contrast, the cells in the node were randomly distributed without any clear direction (Figure 6(b)).

Bottom Line: The distribution pattern of nodes and vessels in the scPVS closely resembled that of the conception vessel meridian and its acupoints.In conclusion, our results newly revealed that the PVS is present in the abdominal subcutaneous tissue layer and indicate that the scPVS tissues are closely correlated with acupuncture meridians.Our findings will help to characterize the PVS in the other superficial tissues and its physiological roles.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151-742, Republic of Korea.

ABSTRACT
The primo-vascular system (PVS) is a novel network identified in various animal tissues. However, the PVS in subcutaneous tissue has not been well identified. Here, we examined the putative PVS on the surface of abdominal subcutaneous tissue in rats. Hemacolor staining revealed dark blue threadlike structures consisting of nodes and vessels, which were frequently observed bundled with blood vessels. The structure was filled with various immune cells including mast cells and WBCs. In the structure, there were inner spaces (20-60 µm) with low cellularity. Electron microscopy revealed a bundle structure and typical cytology common with the well-established organ surface PVS, which were different from those of the lymphatic vessel. Among several subcutaneous (sc) PVS tissues identified on the rat abdominal space, the most outstanding was the scPVS aligned along the ventral midline. The distribution pattern of nodes and vessels in the scPVS closely resembled that of the conception vessel meridian and its acupoints. In conclusion, our results newly revealed that the PVS is present in the abdominal subcutaneous tissue layer and indicate that the scPVS tissues are closely correlated with acupuncture meridians. Our findings will help to characterize the PVS in the other superficial tissues and its physiological roles.

No MeSH data available.