Histological Observation of Canine Acupoints


Myung-cheol Kim mckim@cnu.ac.kr,
Tchi-chou Nam*, Moo-kang Kim, Jong-man Kim, Duck-hwan Kim, Kyoung-youl Lee and Chi-won Song
College of Veterinary Medicine, Chungnam National University, Taejon 305-764
*College of Veterinary Medicine, Seoul National University, Kyunggi-do 440-744, Korea

Abstract | Introduction | Materials & Methods | Results | Discussion | Acknowledgements | References |

Abstract

The purpose of this study was to document the histology of canine acupoints. After needles were inserted to a depth of 1cm into acupoints Neiguan (Inner pass, PC06), Ganshu (Liver Association Point, BL18), Shenshu (Kidney Association Point, BL23) and Pangguangshu (Bladder Association Point, BL28) in 4 dogs, tissue surrounding the acupoints was removed and sectioned serially. Light microscopy was used to observe the structures near each point. Nerve fibres, small vessels and muscle spindles were found around the tip of the needle in every case.

Nerve fibres, small vessels and muscle spindles often occur at another areas, such as skin, subcutaneous tissue and muscle. Therefore, although they were found around the acupoints in this study, many questions remain before one can conclude that these structures relate closely with effect of acupuncture. However, we suggest that they are potential acupoint receptors.

Keywords: Acupoint, Acupuncture, Dog, Histological observation

Introduction

Acupuncture is an ancient Chinese art of healing. Needles are placed in special locations, the acupuncture points (acupoints), to influence certain physiological processes (1-10). Acupoints are specifically designated locations on the body surface. They are sometimes called stimulating points. They are located in or near muscle, blood- or lymph- vessels, or peripheral nerves. Each acupoint is unique not only in its location but in its biophysiological effect (1). According to Chinese medical concepts, acupoints are not isolated sites on the surface of the body of humans and animals, but are linked with visceral organs (7). Acupuncture at specific points activates the defence system of humans and animals via reflex neural effects, autonomic effects, neuroendocrine, endocrine and humoral effects. Sensory input to the hypothalamus is most important in these effects (8).

Questions on the structural basis of acupoints have not resolved despite thousands of years of practical use and more than 40 years of research (3). In recent years acupoints have received a considerable amount of study. These points have a lower skin resistance, radiate more heat, and are localised preferably in muscle valleys, near joints and tendons and near peripheral nerves. They also seem to have certain histological properties that are not found in skin surrounding the acupoint. Because of the different properties, they can be detected by the use of an acupoint detector, which is a sophisticated Wheatstone Bridge (5).

The purpose of this study was to document the histological structures at acupoints in dogs. This study documents the structures near needles inserted into acupoints Neiguan (Inner pass, PC06), Ganshu (Liver Association Point, BL18), Shenshu (Kidney Association Point, BL23) and Pangguangshu (Bladder Association Point, BL28) in dogs.

Materials and Methods

An Acupoint Detector was used to locate acupoints Neiguan, Ganshu, Shenshu and Pangguangshu bilaterally in 4 mongrel dogs, 2 males and 2 females, aged 6 months to 9 years. The Detector was used to search for the point of lowest electrical resistance at locations transposed from human acupoint charts. Needles were inserted into each acupoint to a depth about 1 cm. The dogs were sacrificed with the needles in position.

Relevant samples of tissue around each needle were taken for light microscopy. The specimens were immersed in Schaffer's fixative (alcohol/formaldehyde) and embedded in paraffin, after which 5mm serial sections were prepared. Representative sections of each tissue were stained with hematoxylin and eosin for microscopic examination. The acupoints were observed using light microscope after surrounding tissue of each acupoint was sectioned continuously to the depth of 1cm.

Results

Figures 1, 2 and 3 show photomicrographs of Neiguan in dog 1. Figure 1 shows a hole at the needle tip in the acupoint. Figures 1, 2 and 3 show nerve fibres and arteries around the acupoint.

Figures 4, 5, 6, 7 and 8 show photomicrographs of Ganshu in dog 2. Figures 4 and 5 show a hole at the needle tip in the acupoint. Figure 4 shows many nerve fibres near the acupoint. Also, Figures 4 and 5 show an artery near the acupoint. Figures 6, 7 and 8 show nerve fibres.

Figures 9 and 10 show photomicrographs of Shenshu in dog 3. They show a hole at the needle tip in the acupoint. and also artery near the acupoint.

Figures 11 and 12 show photomicrographs of Pangguangshu in dog 4. They show a hole at the needle tip in the acupoint, and also a muscle spindle near the acupoint.

Discussion

According to traditional Chinese medical theory, each acupoint communicates with a specific organ and reflects the conditions of that organ. When an organ is subject to pathophysiological changes, related acupoints may become tender or show other signs of abnormality, such as altered colour or hardness of the skin at the points. When the points are treated by acupuncture, the effect readily reach the communicating organ through the point and the meridian (4).

Nerve fibres, small vessels and muscle spindles often occur at another areas, such as skin, subcutaneous tissue and muscle. Therefore, although they were found around the acupoints in this study, many questions remain before one can conclude that these structures relate closely with effect of acupuncture. However, we suggest that they are potential acupoint receptors.

Acknowledgements

We thank Phil Rogers MRCVS, Dublin, Ireland for help in the final preparation of this article.

References

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