Changes of gene expression profiles across different phases of vascular calcification in rats

This study investigated the alteration of gene expression profiles in order to gain a deeper understanding into the molecular mechanism involved in different processes of vascular calcification (VC). Sprague Dawley (SD) rats were injected with 300,000 µg/kg vitamin D3 and gavaged with 25 mg/kg nicotine for 8 or 16 weeks to create 8- and 16-week VC calcification groups. Histological analysis and quantification of aortic calcium content were used to determine the severity of vascular calcification. The suppression subtractive hybridization (SSH) method was employed to screen for up and downregulated genes in early and later phases of vascular calcification. Changes in calcium and phosphorus levels in tissue were used as markers of vascular calcification. Quantification of aortic calcium content revealed that vascular calcification might regress over time. In the early phase of vascular calcification, many calcification-promoting genes were upregulated, including ossification, oxidation, and inflammatory genes. In contrast, in later phase of vascular calcification, various calcification-inhibitor genes were highly expressed, including pyrophosphoric acid synthesis genes, glutamate signal peptide-related, reduction activity, and apoptosis regulation genes. The relatively higher expression of calcification-inhibitor genes compared to that of calcification-promoting genes might explain the genetic mechanism leading to the regression of vascular calcification. Therefore, this study provides a genomic basis to facilitate understanding of the molecular mechanism underlying vascular calcification regression.