Objective To investigate the microstructure(blood vessels and nerve fibers)of the skin tissue in "Taichong"(LR 3)region for reveling morphological characteristics of acupoint.Methods Five SD rats were used in the present study.The skin tissue in the region of acupoint LR 3was taken from the dorsum of hind foot following transcardial perfusion with4% paraformaldehyde.Then

the skin samples were sagittally or horizontally cut into sections(20μm or 40μm in the thickness)to be stained with Phalloidin and calcitonin gene related peptide(CGRP)by using fluorescent histochemistry and immunohistochemistry.The labeled vascular structure and nerve fibers were observed and recorded using fluorescent microscope and laser scanning confocal microscope.Results In the skin tissue of LR 3

different types of blood vessels labeled by phalliodin

including capillaries and glomera mainly distributing in the superficial layer of the dermis

and thicker blood vessels and their sub-branches mainly existing in the deeper layer of the dermis and the subcutaneous layer

were found.In addition

CGRP positive nerve fibers were found to run parallel to the thin blood vessels or to gather around the thicker blood vessels.From the subcutaneous layer to the epidermis

blood vessels and nerve fibers coexisted and formed a stereo-network structure.Conclusion In the skin of LR 3area

there exists a stereo-network structure consisting of different types of blood vessels and nerve fibers.Although this structure is not specifically associated with acupoint area alone

this result may provide a new sight to further understand the microstructure of acupoint.