Objective: To observe in vitro effect of intestinal absorption solution of Yuanhu Zhitong preparation on the tension of rat thoracic aortic ring in order to provide new method for pharmacological experiments of traditional Chinese medicine in vitro. Method: Firstly

intestinal absorption solution of Yuanhu Zhitong preparation was prepared by everted gut sac method in vitro at 4 different time points(0.25

0.5

1

2 h). The thoracic aortic was quickly removed after rats were sacrificed by dislocation. Then aortic rings were pre-contracted by KCl(45 mmol·L-1)

and the tension of thoracic aortic ring was observed by adding different volumes (50

100

200

400

800

1 600 μL) of the intestinal absorbed solution from Yuanhu Zhitong preparation

experiments were performed in six replicates (n=6 per group). Result: The vasorelaxation rate was enhanced with the increased volumes of intestinal absorption solution at 2 h

the results indicated that the vasorelaxation was enhanced and a dose-effect relationship was found; Compared with control group of intestinal absorption solution without Yuanhu Zhitong prepation

when the volume of 200 μL was added

P <0.05; when the volume of 400

800

1 600 μL was added

P <0.01. When the volume of 1 600 μL was added

the vasorelaxation of 4 groups were all enhanced

compared with control group of intestinal absorption solution

ther was statistical significance in 0.5 h group

P <0.05; 1 h

2 h group significance at P <0.01

the results indicated that the vasorelaxation was also enhanced with the delayed absorption time of Yuanhu Zhitong preparation and a time-effect relationship was observed. Conclusion: The results show that the intestinal absorption solution of Yuanhu Zhitong preparation may have significant vasorelaxation activity with a manner of dose-effect and time-effect relationship.