[PREPARATION OF ACELLULAR DERMAL MATRIX AS A KIND OF SCAFFOLD FOR CARTILAGE TISSUE ENGINEERING AND ITS BIOCOMPATIBILITY]

Abstract

Objective: To study the preparation method of acellular dermal matrix (ADM) for cartilage tissue engineering and analyze its biocompatibility.

Methods: The dermal tissues of the calf back were harvested, and decelluarized with 0.5% SDS, and the ADM was reconstructed with 0.5% trypsin, cross-linked with formaldehyde, and modified with 0.5% chondroitin sulfate which can promote the proliferation of chondrocytes. And the porosity, cytotoxicity, and biocompatibility were determined. Co-cultured 2nd passage chondrocytes and bone marrow stromal cells in a proportion of 3 to 7 were used as seed cells. The cells were seeded on ADM (experimental group) for 48 hours to observe the cell adhesion. The expressions of mRNA and protein of collagen type II were tested by RT-PCR and Western blot methods, respectively. And the expressions were compared between the cells seeded on the scaffold and cultured in monolayer (control group).

Results: After modification of 0.5% trypsin, the surface of ADM was smooth and had uniform pores; the porosity (85.4% ± 2.8%) was significantly higher than that without modification (72.8% ± 5.8%) (t = -4.384, P = 0.005). The cell toxicity was grade 1, which accords to the requirements for cartilage tissue engineering scaffolds. With time passing, the number of inflammatory cells decreased after implanted in the back of the rats (P < 0.05). The scanning electron microscope observation showed that lots of seed cells adhered to the scaffold, the cells were well stacked, displaying surface microvilli and secretion. The expressions of mRNA and protein of collagen type II were not significantly different between experimental and control groups (t = 1.265, P = 0.235; t = 0.935, P = 0.372).

Conclusion: The ADM prepared by acellular treatment, reconstruction, cross-linking, and modification shows perfect characters. And the seed cells maintain chondrogenic phenotype on the scaffold. So it is a proper choice for cartilage tissue engineering.