[Vascular ageing-related remodeling and differential expression of associated genes: experiment with rats]

To observe the morphological changes in vascular ageing-related remodeling natural aging, screen out genes related to remodeling, analyze the relation between gene differential expression and morphological changes in remodeling, and illustrate possible gene regulation mechanism of vascular ageing-related remodeling.

Sixty male Wistar rats were divided into 4 equal groups according to their ages: 4-month, 10-month, 16-month, and 22-month groups. Their aortas were taken out to undergo HE staining to observe the aortic macrostructure, and undergo Masson staining to observe the relative contents of smooth muscle cells (SMCs) and collagen fibrils (CFs). Gene fishing differential display, RT-PCR, and Western blotting were used to analyze and confirm the genes related to remodeling in ageing vessels and their dynamically differential expression in different months.

The amounts of SMCs and CFs increased along with ageing. 5 differentially expressed gene fragments were selected by gene fishing PCR, which were homologous to the known genes as L-type Ca2+ channel alpha1c subunit (Cacnalc), matrix metalloproteinase 9 (MMP-9), NAD (P) H oxidase alpha subunit (p22-phox), stromal cell-derived factor 1alpha (SDF-1alpha), and caspase 9 (Casp9). The expression levels of Canalc and p22-phox increased with ageing. The expression levels of Canalc and p22-phox of the 16 month group were the highest (0.74 +/- 0.13 and 0.73 +/- 0.12 respectively), both significantly higher than those of the 10 month group (0.12 +/- 0.05 and 0.20 +/- 0.03 respectively, both P <0.01). The expression level of SDF-1alpha decreased with aging. The expression levels of MMP-9 and Casp9 were two-phase, peaking in the 16-month group (0.56 +/- 0.15 and 0.47 +/- 0.16 respectively). Multiple stepwise regression analysis showed that SMC(%) = 10.81Cacnalc-32.34SDF-1alpha +48.11 (r =0.92, P <0.01) and that CF(%) =23.71p22-phox-24.36SDF-1alpha +26.85 (r= 0.93, P <0.01).

With a slow startup, an obvious speedup and a following speed-down, the aortic ageing-related remodeling is not a constant velocity process. The phasic differentiation expression of genes is highly correlated with the vascular ageing-related remodeling. The phasic differentiation expression of Cacnalc, p22-phox, and SDF-1alpha seem to be the key genes for startup, speedup and keeping up of vascular ageing-related remodeling and will be the promising molecular targets for vascular anti-aging.