血管外膜源一氧化氮对内皮素-1诱导的血管平滑肌增殖的影响

Effects of adventitia-derived nitric oxide on the proliferation of vascular smooth muscle induced by endotheline-1

目的 观察血管外膜生成的一氧化氮 (NO)对内皮素 - 1 (ET 1 )诱导的血管平滑肌 (VSM)增殖的影响 ,以探讨血管外膜源NO对血管结构重塑调节的意义。方法 取大鼠胸主动脉 ,去除内皮 ,分以下几组进行组织孵育 1 0h:(1 )完整外膜血管组 ;(2 )单纯中膜组 ;(3)中膜与剥离的外膜共育组 ;(4)中膜与用L N 硝基精氨酸 (L NNA)预处理的外膜共育组。每例胸主动脉剪为二段 ,分两个亚组 :ET (1 0 - 7mol/L)组和对照组。3H 胸腺嘧啶 (3H TdR)掺入法检测各组VSM的细胞增殖。另取大鼠腹主动脉外膜 ,用 1 0 - 8和 1 0 - 7mol/LET 1刺激 4h。Griess法测血管外膜生成的亚硝酸盐 (NO2 )含量 ,3H L 精氨酸 (3H L Arg)标记的同位素法测定外膜一氧化氮合酶 (NOS)活性。结果 (1 )各ET亚组3H TdR掺入比相应对照组分别增加 48.8%～ 71 .9%。 (2 )在 1 0 - 7mol/LET 1刺激下 ,完整外膜组及中膜 +外膜组的3H TdR掺入分别比单纯中膜组低 2 1 .3 %和 2 4 .5 % ;中膜 +L NNA预处理的外膜组3H TdR掺入分别比中膜+外膜组及完整外膜组高 30 8%和 2 5 .4% ,而与单纯中膜组差异无显著性。 (3)与对照组相比 ,1 0 - 8和 1 0 - 7mol/L的ET 1使外膜NOS活性分别增加 1 2 4 %和 1 77% ;使外膜生成的NO2 含量分别增加 88%和 2 2 5 %。结论 实验?

Objective To observe the effect of adventitial nitric oxide(NO) on the proliferation of vascular smooth muscle(VSM) induced by endothlin 1(ET 1) and investigate the significance of adventitia derived NO in vascular remodeling. Methods Rat thoracic aortae ( n =24) were dissected and the endothelia removed. The vessels were divided into four groups ( n =6) as following and were incubated for 10 hours: (1) vessel with intact adventitia; (2) media alone; (3)media and isolated adventitia. (4) media and adventitia pretreated with 10 -5 mol/L L NNA. Every vessel of these groups was cut into two parts, which were incubated in the presence or in the absence of 10 -7 mol/L ET 1 seperately. The proliferation of VSM was measured by 3H TdR incorporation. Adventitia derived NO production (NO 2 ) was determined by Griess method and adventitial nitric oxide synthase (NOS) activity by the transformation of 3H L Arg to 3H L Citrulline respectively. Results (1)The 3H TdR incorporation of VSM in each ET subgroup was significantly elevated by 48.8%～71.9% compared with corresponding control subgroup. (2) When thoracic aortae were stimulated by 10 -7 mol/L ET-1 for 10 hours,the 3H TdR incorporation of VSM in the intact adventitia group and the media+adventitia group decreased by 21.3% and 24.5% compared with the media alone group respectively;the 3H TdR incorporation of VSM in the group of media+adventitia pretreated with L NNA increased by 30 8% and 25.4% compared with the media+adventitia group and the intact adventitia group respectively, and it was not significantly different compared with the media group. (3) After incubation with 10 -8 or 10 -7 mol/L ET 1 for 4 hours, the abdominal aortic adventitial NOS activities were increased by 124% and 177% and adventitia derived NO 2 were increased by 88% and 252% compared with control group respectively. Conclusions The results show that vascular adventitia may inhibit proliferation of medial VSM induced by ET 1, which was mediated by adventitial NOS/NO pathway. Our findings suggest that adventitia derived NO may play an important part in regulating the vascular remodeling of cardiovascular diseases.