衰老大鼠主动脉增龄性重塑及其规律分析

Aortic ageing-related remodeling and analysis on remodeling regularity in the aged rats

目的探讨年龄对主动脉结构及功能的影响,分析主动脉增龄性重塑的主要表现及变化规律。方法健康Wistar大鼠60只,依月龄分为青年组、成年组、中年组和老年组。各组应用超声方法分别进行主动脉壁厚(ADT)和内径检测,离体动脉环试验测定胸主动脉环对乙酰胆碱(Ach)的最大舒张反应性,以及主动脉形态学和比色法检测主动脉一氧化氮(NO)及活性氧(ROS)水平。结果ADT、主动脉内径变化率(ΔAD)、收缩压(SBP)、脉压(PP)、NO、ROS、内膜中膜厚度(T)、血管内径(D)、中膜平滑肌相对含量〔SMC(Aa%)〕、胶原纤维相对含量(Aa%);血管羟脯氨酸含量(HC)、乙酰胆碱诱导的最大舒张百分比(Emax)与年龄明显相关,并且上述指标在各年龄组随增龄变化速率存在差异。结论增龄性动脉重塑过程并非恒速进行,存在一个缓慢起始、加速进展、减速维持的过程。动脉增龄性重塑表现为功能重塑与结构重塑,功能重塑与结构重塑并非同步变化,功能重塑在成年期已经开始;结构重塑主要发生在中年期。

Objective To investigate the ageing-associated structural and functional changes of aorta and analyze the regularity of aortic ageing-related remodeling in healthy mrs during natural aging. Methods Sixty healthy Wistar mrs were divided into young, adult, middie aged and old group. Ultrasonic diagnostics was used to detect the thickness and the diastolic and systolic diameter of aorta. The maximal dilatory response to cumulative doses of acetylcholine （ ACh）was evaluated,and then aorta was detected by morphometry. Nitric oxide＇（NO） and reactive oxygen species （ROS） was detected by colofimetric method respectively. Results The thickness of aorta （ADT）, rate of aortic diameter change （AAD） ,systolic pressure （SBP） ,pulse pressure （PBP） ,nitric oxide （NO） ,ROS,intima-media thickness （T） ,diameter （D） ,the content of smooth muscel cell [ SMC（ Aa% ） ] ,the content of collagen[ CF（ Aa% ） ] ,the content of hydroxyproline, （HC） and maximal dilatory response to Ach （Emax）were correlated with age closely. Furthermore the above items changed with age in each group respectively. Conclusions With a slow startup, an obvious speedup and a following speed-down, the aortic ageing-related remodeling is not a constant velocity process. Functional and structural remodeling are included in the aortic ageing-related remodeling. Meanwhile, there is not a synchronous change between functional and structural remodeling. With startup in adult,functional remodeling is ahead of structural remodeling that happens mainly at the middle age.