增龄对大鼠髂总动脉超微结构的影响

Effect of aging on the ultrastructure of common iliac artery in rats

背景:老化伴随着多个器官结构和功能的进行性下降,动脉血管的结构和功能在老化过程中受到损害。目的:观察增龄对动脉管壁超微结构的影响。方法:成年SD大鼠5只及老年SD大鼠5只,在大鼠麻醉状态下取髂总动脉,放入戊二醛中固定,利用透射电子显微镜观察髂总动脉内膜和中膜的超微结构。结果与结论:①成年大鼠髂总动脉内皮细胞间的连接正常;老年大鼠髂总动脉内皮细胞连接间出现较大的间隙;②成年大鼠髂总动脉中膜平滑肌细胞为收缩表型,细胞外基质中有较多的弹性纤维;老年大鼠髂总动脉平滑肌细胞为合成表型,细胞外基质中胶原纤维明显增多;③老年大鼠髂总动脉观察到有正在死亡的内皮细胞和平滑肌细胞,特征为染色质降解和细胞裂解,而在成年大鼠没有观察到细胞死亡的情况;④结果表明,与成年大鼠相比,老年大鼠髂总动脉内膜增厚,中膜平滑肌细胞呈合成表型,弹性纤维减少、胶原纤维增多。

BACKGROUND:Aging is accompanied by a progressive decline in the structure and function of multiple organs.The structure and function of arterial vessels are impaired during the aging process.OBJECTIVE:To observe the effect of aging on the ultrastructure of arterial wall.METHODS:Five adult Sprague-Dawley rats and five aged Sprague-Dawley rats were selected.The common iliac artery of the rats was taken under anesthesia and fixed in glutaraldehyde,and the ultrasonography of the intima and media of the common iliac artery was observed using a transmission electron microscope.RESULTS AND CONCLUSION:The connection between endothelial cells of the common iliac artery in adult rats was normal,while there was a relatively large gap between endothelial cells of the common iliac artery in aged rats.Smooth muscle cells of the common iliac artery in adult rats exhibited a contractile phenotype,and there were many elastic fibers in the extracellular matrix;in aged rats,smooth muscle cells presented with a synthetic phenotype,and the number of collagen fibers in the common iliac artery was significantly increased.Dead endothelial cells and smooth muscle cells,characterized by chromatin degradation and cell lysis,were observed in the common iliac artery of aged rats,whilst no cell death was observed in adult rats.These findings indicate that the intima of the common iliac artery is thickened,smooth muscle cells present with a synthetic phenotype,the number of elastic fibers is reduced and the number of collagen fibers is increased in aged rats compared with adult rats.