Observation of Coiled Blood Plexus in Rat Skin with Diffusive Light Illumination

Spotlight on acupuncture in laboratory animal medicine

Acupuncture has been practiced for thousands of years, although it is only in the past century that science has worked to unravel the mechanisms behind its use. Literature supporting the efficacious use of acupuncture to treat a variety of conditions has been and continues to be published, including the randomized controlled studies we all appreciate when practicing evidence-based medicine. The use of acupuncture in veterinary medicine has paralleled the trends observed in people, with an increasingly common use to remedy specific medical conditions. These conditions are commonly related to neurological dysfunction or orthopedic pain. Although pain relief is the most common use of acupuncture, numerous other conditions have been shown to improve with this therapy. Laboratory animals are also benefiting from acupuncture. Its use is starting to be incorporated into research settings, although there is still further progress to be made in this field. Acupuncture has been shown to improve clinical conditions and quality of life in laboratory animals, and should be considered as a tool to treat laboratory animals with conditions known to benefit from therapy. Here we review the history, mechanisms of action, and use of acupuncture to treat veterinary patients and laboratory animals.

Observation of a Flowing Duct in the Abdominal Wall by Using Nanoparticles

The primo vascular system (PVS) is being established as a circulatory system that corresponds to acupuncture meridians. There have been two critical questions in making the PVS accepted as a novel liquid flowing system. The first one was directly to show the flow of liquid in PVS and the second one was to explain why it was not observed in the conventional histological study of animal tissues. Flow in the PVS in the abdominal cavity was previously verified by injecting Alcian blue into a primo node. However, the tracing of the dye to other subsystems of the PVS has not been done. In the current work we injected fluorescent nanoparticles (FNPs) into a primo node and traced them along a primo vessel which was inside a fat tissue in the abdominal wall. Linea alba is a white middle line in the abdominal skin of a mammal and a band of fat tissue is located in parallel to the linea alba in the parietal side of the abdominal wall of a rat. In this fat band a primo vessel runs parallel to the prominent blood vessels in the fat band and is located just inside the parietal peritoneum. About the second question on the reason why the PVS was not in conventional histological study the current work provided the answer. Histological analysis with hematoxyline and eosine, Masson’s trichrome, and Toluidine blue could not discriminate the primo vessel even when we knew the location of the PVS by the trace of the FNPs. This clearly explains why the PVS is hard to observe in conventional histology: it is not a matter of resolution but the contrast. The PVS has very similar structure to the connective tissues that surround the PVS. In the current work we propose a method to find the PVS: Observation of mast cell distribution with toluidine blue staining and the PN has a high density of mast cells, while the lymph node has low density.

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

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.