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Modification of the rat aortic wall during ageing; possible relation with decrease of peptidergic innervation.
J L Connat1, D Busseuil, S Gambert
1Université de Bourgogne, IFR 100, UFR Sciences de la Vie, Dijon, France. Jean-Louis.Connat@u-bourgogne.fr
Anatomy and Embryology
|March 6, 2002
Summary
Aging male rats show aortic smooth muscle cell hypertrophy and decreased desmin. Peptidergic innervation, including calcitonin gene-related peptide (CGRP) and substance P (SP), disappears with age, potentially impacting vessel wall stability.
Area of Science:
- Vascular Biology
- Aging Research
- Histology
Background:
- The aging process induces structural and cellular changes in blood vessels.
- Understanding age-related aortic remodeling is crucial for cardiovascular health.
- Previous studies suggest alterations in smooth muscle cells and innervation during aging.
Purpose of the Study:
- To investigate the structural and cellular changes in the male rat aorta from birth to old age.
- To examine the expression of specific biochemical markers and the integrity of peptidergic innervation during aortic aging.
- To correlate these changes with smooth muscle cell hypertrophy and vessel wall stability.
Main Methods:
- Longitudinal study of male and female rat aortas from birth to senescence.
- Histological analysis including TUNEL staining for cell death.
- Immunohistochemistry for vimentin, alpha-smooth actin, and desmin.
- Electron microscopy to assess endothelial and smooth muscle cell morphology.
- Immunohistochemistry for perivascular peptidergic innervation (CGRP, SP, NPY, VIP).
Main Results:
- Male rat aortas exhibited progressive media thickening and decreased nuclear density with age, indicative of smooth muscle cell hypertrophy.
- Desmin staining decreased with age, particularly on the luminal side, while vimentin and alpha-smooth actin remained uniform.
- Aging led to endothelial replacement by cells with pseudopodia and disorganization of elastic laminae.
- Perivascular peptidergic innervation (CGRP, SP, NPY, VIP) was present in young rats but disappeared by one year of age.
Conclusions:
- Aging induces significant structural remodeling in the male rat aorta, characterized by smooth muscle cell hypertrophy and altered extracellular matrix.
- The disappearance of peptidergic innervation during aging may play a role in maintaining aortic wall cellular stability.
- These findings provide insights into the cellular mechanisms underlying age-related vascular changes.