ABSTRACT
AIM: Bone morphogenetic protein (BMP) as polyphenic morphogen can induce the formation of bone and cartilage. This study investigates the effect of BMP on articular cartilage regeneration after periosteal graft. METHODS: Experiments were performed at the Animal Laboratory (absl-3) of Weifang People's Hospital from September 2006 to January 2007. Sixteen New Zealand white rabbits (32 knees) (2.5-3.0 kg) were divided into experimental and control groups randomly, each 8 rabbits (16 knees). The 3.5 mm in diameter of full-thickness articular cartilage defect was made on femoral intercondylar fossa in all rabbits, and 3.5 mm in diameter of periosteum was cut out from the anteromedial part of the upper tibial bone. In the experimental group, the cartilage defect was covered with periosteum, into which 20 ?g BMP and 20% Pluronic were injected. In the control group, the cartilage defect was covered with periosteum, into which the same dosages of 9 g/L saline and 20% Pluronic were injected. All the rabbits were sacrificed in 4, 8 and 12 weeks postoperatively. Motion of joint, conjunction of repair tissue and perienchyma were examined macroscopically. Haematoxylin-eosin staining and toluidine blue staining were used to observe the characteristics of repair tissues. Histological scores on samples in each group were measured by Wakitani score standard at different time points with light microscope. Ultramicrostructure of transplanted tissues was observed with scanning electron microscopy (SEM). RESULTS: Sixteen rabbits were included in the final analysis. Macroscopic observation: 4 weeks after the surgery, the defect was covered with tissue like cartage in the experimental group, and with periosteum in the control group. 8 weeks after the surgery, the surface of the defect was smooth, with boundary unclear in the experimental group. In the control group, the outcome was the opposite. In 12 weeks, cartilage had formed in the experimental group, and tissue like cartilage began to happen in control one. Histological observation: 4 weeks after the surgery, the defect was filled with cells and matrix with abundant proliferation of periosteal cambium layer in the experimental group, and slight proliferation in the control group. 8 weeks after the surgery, the periosteum in the experimental group became fibrocartilage with little hyaline cartilage. Just little fibrocartilage with on hyaline one was detected in the control group. In 12 weeks, the repair tissue in the experimental group approached to normal cartilage. Just fibrous tissue with little fibrocartilage was detected in the control group. Regenerative repair of cartilage defect was better in the experimental group than in the control group (P
