Objective To provide a new method for investigating the histological characteristics of acupoints by obser-ving the microstructure of the lymphatic vessels in the skin tissue of "Taichong"(LR3) and "Yongquan"(KI1) regions. Methods Six male SD rats were used in the present study. The skin tissue of LR3 and KI1 from the hind foot were taken following transcardial perfusion with 4% paraformaldehyde. The skin tissues were cut into sagittal sections with a freezing microtome and stained by fluorescent immunohistochemistry with lymphatic vessel endothelial hyaluronan receptor 1(LYVE-1)

calcitonin gene-related peptide(CGRP)

and phalloidin for displaying the lymphatic vessels

nerve fibers

and blood vessels

separately. The samples were viewed and recorded using fluorescent microscope and laser scanning confocal microscope. Results In the skin tissue of LR3 and KI1 regions

the lymphatic vessels

nerve fibers

and blood vessels were labeled with LYVE-1

CGRP and phalloidin

respectively. The lymphatic capillaries were found to start from the enlarged blind end and distribute in the dermis and subcutaneous tissues with various forms

crisscrossing. Abundant blood capillaries at various thickness distributed around the lymphatic capillaries in a parallel or crossed pattern

intermingled with free nerve fibers. Conclusion The lymphatic capillaries

blood capillaries and nerve fibers extensively distribute in the skin tissues of LR3 and KI1 regions in rats

suggesting an involvement of the immunomodulation in the effects of acupuncture in pathological conditions

despite being not limited to the acupoint regions in the distribution of lymphatic capillaries.