Effects of fibroblast growth factors 2 and low intensity pulsed ultrasound on the repair of knee articular cartilage in rabbits.

To investigate the effect of low intensity ultrasound irradiation combine with fibroblast growth factors (FGF2) on the repair of the knee articular cartilage and to explore its mechanism in rabbit.The model of the rabbit knee joint injury was established. 40 rabbits were divided into four groups, including control group, model group, FGF2 group and FGF2 + low intensity pulsed ultrasound group (FGF2 + LIPU). The knee joints of rabbits were taken at 4 and 8 weeks, respectively. Histopathological changes were detected by Hematoxylin and Eosin stain (HE) and evaluated by Wakitani score. The expression of FGF2 mRNA was detected by Real-time polymerase chain reaction (RT-PCR) and the levels of Collagen I and Collagen II protein were analyzed by Western blotting.In FGF2 group and FGF2 + LIPU group, it was found that the tissues of knee joint were gradually repaired following the change of time. Further, the recovery was better in FGF2 + LIPU group. Cartilage defect areas were filled with cartilage-like cells and the repair surface was fused with surrounding cartilage in FGF2 and FGF2 + LIPU groups. Wakitani scores were consistent with HE results. The expressions of FGF2 mRNA were higher in FGF2 and FGF2 + LIPU group than the model group. Western blotting results showed that the levels of Collagen I and Collagen II protein in FGF2 and FGF2 + LIPU groups were significantly increased compared with that in model group.FGF2 and LIPU combined application on the rabbit knees joint repair is better than FGF2 alone. FGF2 and LIPU combination can promote the synthesis and secretion of collagen in chondrocytes, promote the differentiation and maturation of chondrocytes during the repair of cartilage defects.