Acridine orange staining method to reveal the characteristic features of an intravascular threadlike structure.

A threadlike structure in blood vessels that is considered part of the Bohghan duct system was first reported about 40 years ago. This structure has remained elusive since then due to the inability of other researchers to duplicate the original identification. In this study we identified the characteristic features of this threadlike structure in rats by the use of fluorescent microscope imaging of nuclei stained by acridine orange perfusion. The nuclei of the tissue that comprises the structure are rod-shaped, 10-20 microm long, and aligned in a broken-line striped fashion. The novel technique reported here can differentiate the intravascular threadlike structure from the fibrin strings that normally form during perfusion and can confound the observation procedure. The physiological function of the threadlike structure remains to be elucidated; however, further study may provide a new understanding of mammalian biology in general, and of acupuncture and Oriental medicine in particular.