实验性低血压大鼠肌性动脉的形态结构重建

目的:研究低血压状态下肌性动脉重建的规律,探讨动脉的应力-生长关系.方法:在大鼠左肾动脉分叉处下方缩窄腹主动脉,建立实验性低血压大鼠模型,按不同的时相点在血管组织切片上观察股动脉和胫前动脉的几何形态指标及其显微结构成分的变化.结果:(1)与对照组比较,术后第7天低血压大鼠股动脉壁厚和壁面积、胫前动脉内外径、壁面积开始变小;至术后第21天,动脉各项几何形态指标(除股动脉的壁厚/内径外)均进行性减小,壁面积总负增长率最大(股动脉24.59％,胫前动脉38.66％);(2)血管平滑肌相对含量在术后第7天时已明显减少,术后21 d内总负增长幅度股动脉为17.5％,胫前动脉19.5％.结论:低血压大鼠肌性动脉结构重建的特征为动脉壁面积减小出现早,趋势最稳定,负增长率及总负增长幅度最大.血管平滑肌对应力的反应最敏感,总负增长幅度较大,是影响动脉重建的主要因素.

Remodeling of morphologic structures of muscular arteries in experimental hypotensive rats

Objective:To study the rule of remodeling morphologic structures of muscular arteries and the relationship between stress and growth of muscular arteries in hypotension. Methods: A hypotensive model was established in rats by constricting abdominal aorta below the orifice of the left renal artery. The changes of the morphometric parameters and microstructral components of the arteries were observed at different phases. Results: (1)Wall thickness, cross-sectional area of femoral artery, inner and outer diameter and cross-sectional area of anterior tibial artery were less than those of the control on the 7th day after operation(P<0.05,P<0.01). Changes of all morphometric parameters but wall thickness/inner diameter were obviously different from control on the 21st day(P<0.05). In all the parameters the total negative increase rate of wall thickness was the largest (24.59% in femoral aorta and 38.66% in anterior tibial artery); (2)The relative amount of smooth muscle decreased obviously on the 7th day(P<0.01), and its total negative increase was 17.5% in femoral artery and 19.5% in anterior tibial artery 21 d after operation. Conclusion: Of all parameters the decrease of the wall area occurs earlier than others, and its tendency of change is the stablest, its negative increase rate and total negative increase amplitude are the greatest, so it is the characteristic guideline. Smooth muscle is most sensitive to stress, and its total negative increase amplitude is great, so it's the important factor for arterial remodeling.