Motility and function of smooth muscle cells in a silk small-caliber tubular scaffold after replacement of rabbit common carotid artery

Abstract

Cell infiltration and proliferation are prerequisites for tissue regeneration and repair. The aim of the present study was to evaluate the motility and function of vascular smooth muscle cells (SMCs) in a silk-based small-caliber artificial blood vessel (SFTS) following implantation to replace the common carotid artery in rabbits. Hematoxylin and eosin (HE) staining showed a number of SMCs clearly distributed in the scaffold at 1month, which gradually increased up to 80-90% of autologous blood vessels at 3months and was 100% at 12months. Smooth muscle myosin heavy chain (SM-MHC) and α-smooth muscle actin (α-SMA) are specific markers of SMCs. Real-time PCR results showed that the gene expression level of α-SMA in SFTSs was significantly down-regulated within 6months, except in the early stage of implantation. The relative expression level of α-SMA at 12months was five times higher than that at 3months, indicating that SMCs phenotype transformed from synthetic to contractile. The SM-MHC+ and α-SMA+ SMCs were disorderly distributed in the scaffolds at 1month, but became ordered along the circumference 6months after grafting as shown by immunohistochemistry. Results indicated that the bionic SFTSs were able to induce in situ angiogenesis in defects.