Modified acellular dermal matrix for chondrocyte implantation in repairing cartilage defects of rabbits

BACKGROUND: Acellular dermal matrix possesses good flexibility and simple trimming. The intracutaneous or subcutaneous injection of acellular dermal matrix powder has fibroblast migration and collagen deposition. It has been widely used in plastic and reconstructive surgery. OBJECTIVE: To explore the feasibility of reconstructed acellular dermal matrix as a scaffold for chondrocyte implantation. DESIGN, TIME AND SETTING: Comparative observation. The study was performed at the Peking University Medical Department and Beijing Jishuitan Hospital between August 2003 and February 2007. MATERIALS: Neonatal calf dermis was provided by Beijing Yuanheng Shengma Biology Technology Research Institute. A total of 24 healthy adult SD rats, weighing 250 g, regardless of gender, and 36 New Zealand rabbits, aged 3 months, were selected. METHODS: Circled digit oneCalf full-thickness back skin was incubated with cell free buffer or ABS/AES for decellularization, followed by surface modification using growth factors. Circled digit twoThree rectangle skin flaps at two sides of the spinal cord of rats were made, and implanted with acellular dermal matrix. The implants were harvested at 2,6, and 12 weeks postoperatively. Circled digit threeThe rabbits were divided into experimental and control groups. The cartilage was obtained from the left articular facet to isolate chondrocytes. The chondrocytes were seeded on the acellular dermal matrix. The cartilage defect was made on the right hind limb of experimental rabbits, and implanted with acellular dermal matrix containing autologous chondrocytes. Biogel was dropped on the surface of carrier. In the control group, the cartilage defect was made on the right hind limb of rabbits and the wound was sutured. Two rabbits from control group and 5 from experimental group were selected respectively at 4, 12 and 24 weeks postoperatively. MAIN OUTCOME MEASURES: Cross-linking effect comparison; repair effect of rabbit bone defects. RESULTS: Circled digit oneThe acellular dermal matrix cross-linked by glutaraldehyde demonstrated an obvious inflammatory reaction with tissue bleeding and necrosis. Conversely, ADM treated with water-soluble cross-linking agent caused displayed good histocompatibility. Circled digit twoThe cartilage defects were repaired completely; the attached cells survived and proliferated and the acellular dermal matrix was degraded after 24 weeks of surgery. CONCLUSION: The acellular dermal matrix decellularized with cell free buffer, digested with digestive buffer, cross-linked by water-soluble cross-linking agent, and further decorated with growth factor exhibited good histocompatibility, and was suitable for cell attachment and growth. The acellular dermal matrix scaffold almost degrades in the rabbits, with no rejection, and the bone defects were repaired after 24 weeks.