In vitro study of bioactivity of homemade tissue-engineered periosteum.

This study was aimed to evaluate in vitro bioactivity of tissue-engineered periosteum (TEP) which was fabricated by coupling either rabbits' MSCs or osteodifferentiated MSCs (O-MSCs) with porcine small intestinal submucosa (SIS), and that produced two kinds of TEPs (M1=MSCs+SIS and M2=Osteoblast+SIS). The cell adherence was observed under scanning electronic microscopy (SEM). Cell proliferation was measured by 3-[4,5-dimethylthiazol-2yl]-2,5-diphenyl-2 H-tetrazoliumbromide (MTT) test. In vitro osteogenetic potential of TEPs was evaluated kinetically at 0, 5, 10 and 15 d by measuring alkaline phosphatase (ALP) activity, and semi-quantitative assay of osteocalcin and collagen type I expression with Western blot. SEM indicated that either MSCs or O-MSCs could adhere and survive on SIS, but MTT test revealed that SIS was more preferable for O-MSCs than MSCs in proliferative aspect. In contrast, ALP activity, osteocalcin and collagen type I expression of M2 were higher than M1 in general. Kinetically, osteocalcin and collagen type I expression demonstrated a continuous increase, while ALP activity of both groups was displayed an early peak around the fifth day, followed a decrease trend. In conclusion, TEP, especially M2, has an active osteogenesis and is promising for in vivo bone defect reparation via a supposed biomimetic procedure of intramembranous ossification.