Fluid Flow along Venous Adventitia in Rabbits: Is It a Potential Drainage System Complementary to Vascular Circulations?

Background

Our previous research and other studies with radiotracers showed evidence of a centripetal drainage pathway, separate from blood or lymphatic vessels, that can be visualized when a small amount of low molecular weight tracer is injected subcutaneously into a given region on skin of humans. In order to further characterize this interesting biological phenomenon, animal experiments are designed to elucidate histological and physiologic characteristics of these visualized pathways.

Methods

Multiple tracers are injected subcutaneously into an acupuncture point of KI3 to visualize centripetal pathways by magnetic resonance imaging or fluorescein photography in 85 healthy rabbits. The pathways are compared with venography and indirect lymphangiography. Fluid flow through the pathways is observed by methods of altering their hydrated state, hydrolyzing by different collagenases, and histology is elucidated by optical, fluorescein and electron microscopy.

Results

Histological and magnetic imaging examinations of these visualized pathways show they consist of perivenous loose connective tissues. As evidenced by examinations of tracers’ uptake, they appear to function as a draining pathway for free interstitial fluid. Fluorescein sodium from KI3 is found in the pathways of hind limbs and segments of the small intestines, partial pulmonary veins and results in pericardial effusion, suggesting systematical involvement of this perivenous pathway. The hydraulic conductivity of these pathways can be compromised by the collapse of their fiber-rich beds hydrolyzed by either of collagenase type I, III, IV or V.

Conclusions

The identification of pathways comprising perivenous loose connective tissues with a high hydraulic conductivity draining interstitial fluid in hind limbs of a mammal suggests a potential drainage system complementary to vascular circulations. These findings may provide new insights into a systematically distributed collagenous connective tissue with a circulatory function and their potential relevance to the nature of acupuncture meridians.     

高速逆流色谱结合半制备液相色谱制备甘青青兰中3种活性成分

采用高速逆流色谱（HSCCC）结合液相色谱法制备甘青青兰（Dracocephalum tanguticum Maxim.）中绿原酸、胡麻甙-6″-乙酯、迷迭香酸,建立快速分离制备甘青青兰中活性成分的方法。采用半制备型高效液相色谱（SP-HPLC）富集甘青青兰乙酸乙酯萃取物中绿原酸、胡麻甙-6″-乙酯、迷迭香酸,再用制备液相（Pre-HPLC）和HSCCC对富集物进行分离纯化,获得54 mg化合物Ⅰ、130 mg化合物Ⅱ和200 mg化合物Ⅲ,纯度分别为96.9%、97.9%和95.1%,经核磁共振碳谱（¹³CNMR）和氢谱（¹HNMR）分别鉴定为绿原酸、胡麻甙-6″-乙酯和迷迭香酸。本实验方法适用于甘青青兰乙酸乙酯萃取物中绿原酸、胡麻甙-6″-乙酯和迷迭香酸的分离制备,并避免了传统分离方法操作繁多、试剂消耗量大、不可回收等弊端,为分离甘青青兰活性成分、制备对照品等研究提供了参考依据。