In vitro study of nano-HA/PLLA composite scaffold for rabbit BMSC differentiation under TGF-β1 induction

The aim of this study is to investigate the effects of differentiation of rabbit bone marrow mesenchymal stem cells (rBMSCs) into chondrocytes induced by transforming growth factor-beta1 (TCP-beta 1) composite poly-1actide-co-glycolic acid/nano-hydroxyapatite (PLLA/nano-HA) to the construction of biomimetic artificial cartilage in vitro. In the low-temperature extrusion preparation of PLLA/nano-HA composite porous scaffolds, rBMSCs were isolated and cultured to third generation in vitro, induced by TGF-beta 1-contained special inducing system into chondrocytes, 14 d later, identified by toluidine blue and type II collagen immunohistochemistry staining, and then the differential chondrocytes composite into the PLLA/nano-HA composite porous scaffolds, using scanning electron microscopy (SEM) to observe the growth conditions and cell attachment on the composite in the 7th,14th, and 21st day and to gather cells on composite in the 7th, 14th, and 21st day of cell. RT-PCR is used to detect the expression of aggrecan (Col2A1 in mRNA) and Western blot for detection of the expression of type II collagen of the attached cells. rBMSCs can differentiate into chondrocytes when induced, and the differentiation of chondrocytes secreting GAG by toluidine blue staining and type II collagen immunohistochemistry staining was positive; SEM confirm the cells distribution evenly, stretching well in composite. RT-PCR of aggrecan, Col2A1 in mRNA, and Western-blot of type II collagen expression in the differentiation of chondrocytes have different levels. Using TGF-beta 1 containing special inducing system induced rBMSCs into chondrocytes, then into compounds of PLLA/nano-HA composite porous scaffolds, and cell carrier complex proliferated well and secreted the chondrocyte-specific extracellular matrix stably, successfully constructing artificial bionic in vitro.