摘要
目的:研究增龄对离体大鼠主动脉内皮依赖性舒张的影响。方法:成年及老年大鼠各20只,利用组织器官水浴系统,通过乙酰胆碱、N-硝基左旋精氨酸,测量离体主动脉环的舒张反应变化(%)。同时利用免疫组织化学方法观察诱导型一氧化氮合酶(induciblenitricoxidesynthase,iNOS)和内皮型一氧化氮合酶(endothelialnitricoxidesynthase,eNOS)在不同年龄大鼠主动脉中的表达。结果:①老年组大鼠主动脉环对1×10-8,1×10-7,1×10-6,1×10-5,1×10-4mol/L乙酰胆碱诱发的内皮依赖舒张反应(3.13±0.85)%,(12.60±2.18)%,(25.23±4.63)%,(37.73±6.95)%,(50.78±3.58)%均较成年组明显减弱,两组之间有显著差异(P<0.01)。②离体大鼠主动脉环环经1×10-4mol/LNNLA预处理20min,阻断一氧化氮合酶(nitricoxidesynthase,NOS)后,同样剂量的乙酰胆碱不再诱发上述内皮依赖性舒血管反应。③eNOS组:在老年组血管内膜层可见棕褐色的阳性反应颗粒120.524±2.037,但较成年组相比,可发现阳性反应明显减弱。iNOS组:成年组内膜及中膜层可见较弱的棕褐色阳性反应颗粒沉在老年组(112.371±1.64),阳性反应明显增强。结论:随增龄,血管内皮分泌的一氧化氮逐渐减少,导致血管内皮依赖性舒张减弱;NOS的异常表达对一氧化氮减少起着重要的作用。
AIM:To study the effects of aging on aortic endothelium- dependent vasodilat ion in isolated rat aorta. METHODS:The changes of vasodilation of isolated aortic rings from 20 adult an d 20 old- age rats were detected using tissue organ bath system, acetylcholine( Ach),and N- nitro- L- arginine(NNLA).The expression of inducible nitricoxide synthase(iNOS) and endothelial nitricoxide synthase (eNOS) was observed by immun ocytochemistry in different age groups. RESULTS: Endothelial dependent relaxation of aortic rings(1× 10-8, 1× 10-7, 1× 10-6, 1× 10-5, and 1× 10-4 mol/L) induced by Ach[(3.13± 0 .85)% ,(12.60± 2.18)% ,(25.23± 4.63)% ,(37.73± 6.59)% ,and(50.78± 3.58) %]in old rats obviously decreased compared with in adult rats( P< 0.01) .Aft er 20 min pretreatment with NNLA(1× 10-4 mol/L) to inhibit nitricoxide syntha se(NOS).Ach of the same dose could not induce endothelium- dependent relaxation in the isolated aortic rings of old and adult rats.eNOS group:brown particles w ere seen in endothelial cell layers of adult rats,and in old rats,positive stain ing particles (120.524± 2.037) were weakened compared with those of adult rats. INOS group:there were fewer brown particles in endothelial cell layers of adult rats;but in old- age group there were lots of brown particles (112.371± 1.649) ,most of which were distributed in the media. CONCLUSION:With aging and NO decrease,endothelium- dependent relaxation decl ines significantly.In L- Arg- NO- pathway,abnormal expression of NOS has majo r effects on the synthesis of NO.The expression of eNOS weakens,and the expressi on of iNOS enhances with age.
出处
《中国临床康复》
CSCD
2004年第3期582-583,T002,共3页
Chinese Journal of Clinical Rehabilitation
