Abstract: Objective To observe the effect of soft tissue crush injury on the tensions of thoracic aortic rings（TARs） in rats and to investigate the potential roles of nitric oxide in the change of the tensions. Methods Thirty adult SD rats were randomly divided into control group and crush injury （8 h and 16 h after injury） groups. Two kinds of TARs （one with endothelium and the other without endothelium） in vitro were prepared. In the TARs with endothelium, the tensions induced by phenylephrine（PE）, acetylcholine（Ach）, calcium ionophore A23187 and angiotensin Ⅱ（AngⅡ） were measured by the vascular tension detective technique. Then the TARs with endothelium were preincubated with nitric oxide synthase inhibitor N-nitro-L-arginine（L-NNA） for 20 minutes, the tensions induced by PE and AngⅡ were measured again. In the TARs without endothelium, the tensions induced by PE and AngⅡ were measured by the same method. Results In the TARs with endothelium, the tension of relaxation induced by cumulative doses of Ach and A23187 decreased significantly in 8 h and 16 h groups. The tension of contraction induced by cumulative doses of PE and AngⅡ also decreased significantly（P<0.05）. The tension of contraction increased after the preincubation with L-NNA. In the TARs without endothelium, the tension of contraction induced by PE and AngⅡincreased comparing to that of TARs with endothelium. Conclusion The soft tissue crush injury can influence the tensions of TARs in rats and the vascular-derived NO can mediate the effects.

Key words: forensic pathology, soft tissue injuries, crush, nitric oxide, aorta, thoracic, rats, tension