Abstract: Objective: To explore the effects of SR59230A on the tension and microRNA (miRNA) expression of rat thoracic aorta.Methods: Forty-four SD rats were used in the experiment. Twenty-four rats were used to observe the effect of SR on the tension of thoracic aortic rings. Another 20 rats were randomly divided into control (n=10) and SR group(n=10). Rats in SR group were injected SR intraperitoneally,and in control group were given 0.9% of saline. After 5 weeks, the blood pressure of all rats were measured. Then the tension to NA and the expression of miRNA of thoracic aorta rings were measured.Results: (1) The tension of thoracic aortic rings responding to 30 mmol/LKCl were increased by pretreatment of SR (P<0.05); (2) After 5 weeks injection of SR, systolic pressure was increased (P<0.05); (3) The tension in SR group was increased in presence of 1 μmol/L and 10 μmol/L of NA (P<0.05,P<0.01). (4) After 5 weeks of SR in vivo application,18 miRNA were down-regulated, 7 of them had statistical significance, they were rno-miR-143-3p, rno-miR-29b-3p, rno-miR-31a-5p, rno-let-7b-5p, rno-miR-214-3p, rno-miR-222-3p and rno-miR-352; 11 miRNA were up-regulated, 4 of them had statistical significance, they were rno-miR-206-3p、rno-miR-223-3p、rno-miR-342-3p and rno-miR-499-5p respectively.Conclusion: SR59230A increased the tension of rat thoracic aorta. In vivo administration of SR led to increase of systolic pressure of rat,down-regulation of rno-miR-143-3p、rno-miR-29b-3p、rno-miR-31a-5p、rno-let-7b-5p、rno-miR-214-3p、rno-miR-222-3p、rno-miR-352 and up-regulation of rno-miR-206-3p、rno-miR-223-3p、rno-miR-342-3p and rno-miR-499-5p.

Key words: rat, SR59230A, thoracic aorta, tension, microRNA