Effect of water decoction of the Gastrodia elata Bl on vasodilation of rabbit aorta in vitro / 中国组织工程研究

ABSTRACT

BACKGROUND: Recent research has shown that Gastrodia elata Bl (GEB) has a cardiovascular protective effect and relaxes blood vessels with important therapeutic implication to treat coronary heart disease and hypertension. However, the mechanism is still unclear.OBJESTIVE To study the effect of the water decoction of GEB on noradrenaline (NA) or KC1 precontracted aortic rings and the possible mechanisms.DESIGN: A grouping observational experiment of animal tissue in vitro.SETTING: Department of Physiology, North Sichuan Medical College.MATERIALS Twelve health New Zealand、White rabbits (2.5-3.0 kg, 7-8 months, SPF, either gender) were provided by the Experimental Animal Center, North Sichuan Medical College. The water decoction of GEB was prepared by Huirentang Drugstore and diluted into 10%, 20%, 40%and 80% solution. The following drugs were used Nω-nitro-L-arginine (L-NNA, Sigma, USA); Methylene blue (MB, Merck, Germany); Acetylcholine (ACh) and Propranolol (Prop) (The Second Beijing Pharmaceutical Company, China); Indomethacin (Indo, Jingsu Taicang Pharmaceutical Company, China).METHODS: The experiment was performed in the Institute of Materia Medica, North Sichuan Medical College between January 2006 and January 2007. Rabbit smooth muscles of aortic rings were isolated and precontracted with NA. The thoracic aortic rings were treated with GEB with cumulative concentrations of 1.0,2.0,4.0,8.0 and 16g/L respectively. The aortic tings were treated with one of the following signaling inhibitors for 15 minutes, including 1×104mol/L L-NNA, 1×10-5mol/L MB, 1×10-5mol/L Indo and 1×10-5mol/L Prop. The changes of tension in aortic rings were recorded using a force transducer and processed by BL-410 Experimental System of Biological Function. The aortic rings were incubated with 8g/L GEB followed by the NA and KCl dose response experiments.MAIN OUTCOME MEASURES: Blood vessel tension ex vivo.RESULTS: GEB did not change the resting tension of rabbit aortic rings, but GEB treatment resulted in an obvious relaxation in NA-precontracted aortic rings (r=0.85, t=18.45, P＜0.01) and the relaxant effect was dose-dependent. The relaxant effect of GEB was significantly reduced by removal of endothelium and by treatment with 1×10-4mol/L nitric oxide synthase inhibitor L-NNA (1×10-4mol/L), or 1×10-5mol/L guanylyl cyclase inhibitor methylene blue (1×10-5mol/L MB), but not by treatment with prostaglandin synthase inhibitor of blockage of the adrenergic β-receptor (1×10-5mol/L Prop). In addition, GEB (8g/L) decreased the dose response curves of aortic rings to NA or KCl in the absence of endothelial cells, and changed the PD2 values for NA from (6.90±0.93)mol/L in control group to[(5.61±0.70)mol/L, t=2.41, P＜0.05] and for KCl from (1.53±0.55) mmol/L in control group to (1.10±0.25)mmol/L, t=3.82, P＜0.05] respectively.CONCLUSION: GEB can relax isolated rabbit aorta not only in an endothelium-dependent, nitric oxide involved manner, but also is related to blockage of receptor-operated and potential-dependent calcium channels.