Effect of propofol on endothelial nitric oxide synthase and inducible nitric oxide synthase expression in thoracic aorta of hypertensive rats

Objective To investigate the effect of propofol on endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) expression in thoracic aorta of hypertensive rats.Methods Healthy SD rats of both sexes weighing 240-280 g were used in this study.Hypertension was induced by subcutaneous deoxycorticosterone 25 mg/kg twice a week for consecutive 7 weeks.Sixty-four hypertensive rats were randomly divided into four groups (n ＝ 16 each):hypertension group (group H),low,medium and high dose propofol group ( groups P1,P2,P3 ).Groups P1,P2 and P3 received infusion of propofol at a rate of 20,30 and 40 mg* kg- 1 · h- 1 for 3 h respectively,while group H received equal volume normal saline instead of propofol.Mean arterial pressure (MAP) was monitored and recorded before,1 h and 3 h after the start of propofol or normal saline infusion.All animals were sacrificed at 3 h of intravenous administration.Blood samples were collected by taking out the eyeballs for determination of serum NO concentrations by nitrate reductase method.The expression of eNOS mRNA,iNOS mBNA was determined by reverse transcription-polymerase chain reaction.The expression of eNOS and iNOS protein was determined by Western blot.Results Compared to group H,MAP was decreased significantly,the serum NO concentrations were increased significantly,the expression of eNOS mRNA and protein in thoracic aorta was up-regulated,and the expression of iNOS mRNA and protein in thoracic aorta was down-regulated in a dose-dependent manner in groups P1,P2 and P3 ( P < 0.05 or 0.01 ).Conclusion Propofol can down-regulate iNOS expression and up-regudate eNOS expression in endothelial cells of thoracic aorta and promote NO release in hypertensive rats,Which is the mechanism of propofol decreasing pressure. Key words: Propofol; Hypertension; Nitric oxide synthase type Ⅲ; Nitric oxide synthase type Ⅱ ; Aorta,thoracic