Biocompatibility and experimental study on rabbits full-thickness articular cartilage defects repaired by a new biomimetic designing of a multi-grade compositions

Abstract

Objective To observe the biocompatibility of a biomimetic designing of a multi-grade compositions in repairing articular cartilage and subchondral bone in animal bodies and repair the fullthickness defects in articular cartilage with the compositions and to study the regenerated cartilage histomorphologically. Methods Biocompatibility study: Acute general toxicity test, Haemolysis test, subcutaneous implantation test and chronic toxicity test. Articular cartilage defects repaired experimental study :The models of defects in articular cartilage were made artificially in both condylus lateralis femoris of mature rabbits. Implanted with the biomimetic designing of a multi grade compositions randomly at one side as the experimental group and the other side were untreated as the control group. The rabbits were killed at 4, 6, 8and 12 weeks after operation, respectively, with 6 ones at each time, and the macroscopic, histological, ultrastroctural examinations and semi-quantity cartilage scoring employing Wakitanifa repaired cartilage value system were performed. Results Biocompatibility study: (1) The rabbits' weight in experimental group kept growing .(2) Haemolysis rate of rats to different concentrations of diffusion solution was＜5%.(3) In chronic toxic reaction, rabbits' liver and kidney function was not different compared with the control groups at 12weeks and the index before operation. Articular cartilage defects repaired experimental study: 4-8 weeks after operation, the defects in the experimental group were partly filled with hyaline cartilage. Twelve weeks after operation, the defects in the experimental group were completely filled with mature hyaline cartilage.However, fibrous tissues were seen in the control group all the time. At 4, 6, 8, and 12 weeks postoperatively, the Wakitanifa cartilage scores were (7.60±0.98), (5.69±0.58), (4.46±0.85) and (4.35±0.12), respectively,in the experimental group and (10.25±1.05), (9.04±0.96), (8.96±0.88) and (8.88±0.68), respectively, in the control group. Differences between the control group and the experimental group were significant. Conclu sion The biomimetic designing of a multi-grade compositions has good biocompatibility and may induce cartilage regeneration to repair the full-hickness defects of articular cartilage. Key words: Cartilage; Wounds and injuries; Biocompatible materials