Method for recording tension changes of small pulmonary artery and vein using the isolated vessel tension measurement system

Objective To establish a standardized method for isolated pulmonary artery and vein rings with different diameter, pressure and length, which could provide a more scientific method for in vitro study of pulmonary vessel diseases. Methods Male SD rats were anesthetized, and the right ventricular systolic pressure were measured. Small pulmonary artery and vein rings with 200-400 μm in diameter and 2 mm in length were prepared by dissecting pulmonary arteries and veins. The pulmonary vessel rings were mounted in the organ bath by 2 stainless steel wires with diameter of 40 μm. Then the internal circumference of the vessel rings was increased gradually with 100 μm per step. At the same time the vascular tension was recorded by the Myograph System and Acknowledgement data acquisition system, and subsequently the passive length-tension exponential curve was made. The initial tension of the rings was set, equilibrated for another 30 min, and then stimulated with 60 mmol/L KCl 3 times, and the best contractile reactivity was achieved. The contractile reactivity of pulmonary artery rings and endothelial integrity were detected by exposure to 1 μmol/L phenylephrine(PE) and 10 μmol/L acetylcholine(Ach), while the contractile reactivity of pulmonary vein rings was detected by exposure to 1 μmol/L U46619 and 10 μmol/L papaverine. Results The contraction and relaxation effects of the pulmonary artery rings reached 0.39 mg and 92% when they were stimulated by 1 μmol/L PE and 10 μmol/L Ach. The contraction and relaxation effects of pulmonary vein rings were up to 0.13 mg and 84% when they were exposed to 1 μmol/L U46619 and 10 μmol/L papaverine, respectively. Conclusion Pulmonary artery and vein rings with appropriate basal tension and optimal vasodilator activity were prepared, and a standardized method of tension experiment for isolated pulmonary artery and vein rings established. Key words: Pulmonary artery ring; Pulmonary vein ring; Vascular tone; Vessel normalization