Effects of Human Insulin Gene Transfection on the Adipogenic Differentiation of Human Umbilical Cord Mesenchymal Stem Cells in Silk Fibroin Scaffolds in Vitro

The resorption of the transplanted fat over time limited the use of autologous fat for the reconstruction of soft tissue defect. Tissue engineering (TE) adipose with silk fibroin scaffold could be a promising substitute for soft tissue filling. In this study, we try to develop a tissue engineering adipose in vitro by seeding silk fibroin scaffold with human umbilical cord mesenchymal stem cells (hUCMSCs) after transfected with recombinant human insulin gene lentivirus. Our aim was to observe the effects of the insulin gene transfection on the adipogenesis of hUCMSCs when cultured with silk fibroin scaffolds. The hUCMSCs infected with recombinant lentiviral pLenti6.3-insulinIRES-EGFP were seeded on silk fibroin scaffolds and cultured in adipogenic differentiation medium for 5 7 days. The expression of adipogenic gene PPARγ-2 was tested by RT-PCR after 7 days culture of adipogenic induction. The accumulation of cytoplasmic droplets of neutral lipids was assessed by Oil Red O staining. The RNA and protein expression of transfected insulin gene in hUCMSCs were detected by QPCR and western blot. The effect of recombinant lentivirus transfection on the growth and proliferation of hUCMSCs was observed by MTT test. We observed that the 2-∆∆Ct value of insulin gene expression of hUCMSCs in the transfected group was 300.25 times higher than that in the untransfected group. The western blot showed that a positive band was discerned at the site of a relative molecular mass of 8 × 103 Dalton in transfected group. After adipogenic culture for 7 days, under the fluorescent inverted phase-contrast microscope, after Oil Red O staining, a lot of adipocytes appeared in silk fibroin scaffold; round adipose droplets showed intracellularly; the size of the adipocytes was not homogenous, and the density of adipocytes in transfected group was significantly higher than that in untransfected group (P = 0.007, P < 0.01). Corresponding author.