Vascular disorders are a major problem as their pathophysiology has not been fully understood, therefore animal models are implemented to extrapolate the results obtained on animals to humans. The isolated tissue bath technique is a classical pharmacological tool for evaluating concentration-response relationship and to measure the isometric contraction of isolated large conduit (thoracic aorta) arteries. The aim of this study was to investigate the stability of thoracic rings from 10-week-old male Wistar rats during 2, 4, 6 and 8 hours of incubation. The vascular response to potassium chloride (KCl), noradrenaline (NA) and acetylcholine (ACh) was analyzed in tissue baths. In addition, histological morphology of the aortic rings after the incubation period was studied. No difference was observed in the contraction to NA (mg of tension, 8 hour: 1711 ± 53.85 vs. control: 1567 ± 48.55, P>0.0928) and vasodilation to ACh (% relaxation, 8 hour: 64.7 ± 4.05 vs. control: 71.21 ± 3.613, P>0.05) of the thoracic rings among the investigated groups of rats. The integrity of the tunica media and adventitia structure remained unaffected during the first 6 hours of incubation. Within 8-hour incubation, slight degeneration of the tunica media smooth muscle structure took place. The results indicate that incubation carried up to 6 hours constitutes a reliable experimental model, as to the NA and ACh application. However, longer experiments should be performed with caution due to the appearance of some initial structural changes of the tunica media smooth muscle cells of a rat aorta starting from the eighth hour of incubation. Thus, it is reasonable to carry out similar experiments with an extended range of experimental reagents, and in different pathological conditions to verify the results obtained in this experiment.  

24.2.2019