The effect of core decompression on local expression of BMP-2, PPAR-γ and bone regeneration in the steroid-induced femoral head osteonecrosis

Abstract

BackgroundTo investigate the efficacy of the sole core decompression surgery for the treatment of steroid-induced femoral head osteonecrosis.MethodsThe model was established by administration of steroids in combination with horse serum. The rabbits with bilateral femoral head osteonecrosis were randomly selected to do the one side of core decompression. The other side was used as the sham. Quantitative RT-PCR and western blot techniques were used to measure the local expression of BMP-2 and PPAR-γ. Bone tissues from control and operation groups were histologically analyzed by H&E staining. The comparisons of the local expression of BMP-2 and PPAR-γ and the bone regeneration were further analyzed between different groups at each time point.ResultsThe expression of BMP-2 in the osteonecrosis femoral head with or without decompression was significantly lower than that in normal animals. BMP-2 expression both showed the decreasing trend with the increased post-operation time. No significant difference of BMP-2 expression occurred between femoral head osteonecrosis with and without decompression. The PPAR-γ expression in the femoral head osteonecrosis with and without core decompression both was significantly higher than that in control. Its expression pattern showed a significantly increased trend with increased the post-operation time. However, there was no significant difference of PPAR-γ expression between the femoral head osteonecrosis with and without decompression at each time point. Histopathological analysis revealed that new trabecular bone and a large number of osteoblasts were observed in the steroid-induced femoral head osteonecrosis with lateral decompression at 8 weeks after surgery, but there still existed trabecular bone fractures and bone necrosis.ConclusionsAlthough decompression takes partial effect in promoting bone regeneration in the early treatment of femoral head osteonecrosis, such an effect does not significantly improve or reverse the pathological changes of femoral head necrosis. Thus, the long-term effect of core decompression in the treatment of steroid-induced femoral head osteonecrosis is not satisfactory.

Low-intensity Pulsed Ultrasound Enhances Bone Repair in a Rabbit Model of Steroid-associated Osteonecrosis

“…It has been established that BMP-2 plays a central role in initiating bone formation [42], stimulating osteogenic differentiation of MSCs [9], and increasing osteoblast activity [10]. The lower BMP-2 expression could reduce local MSC activity and the capacity for bone repair [32]. In our study, LIPUS increased BMP-2 mRNA and protein expression in femoral heads with steroid-associated osteonecrosis.…”

“…femur (Fig. 4), which is identified as a potential cause of femoral head osteonecrosis [32]. The percentage of empty osteocyte lacunae in the LIPUS group (17% ± 4%; 95% CI, 15%-20%) was 51% lower (p = 0.002; Table 2) than in the control group (26% ± 9%; 95% CI, 21%-32%).…”

“…44Ct = 4Ct 1 À 4Ct 2 . 4Ct 1 is the value of the housekeeping gene 18S and 4Ct 2 indicates the Ct value of the target gene [7,32]. The results of each group are presented as mean ± SD.…”

“…The images were analyzed with Bandscan 5.0 (Glyko Inc, Novato, CA, USA) to calculate the intensity of the bands. The ratio of the intensities of the target genes and b-actin bands was used to represent the level of protein expression [32]. The results of each group are presented as mean ± SD.…”

“…Steroids, commonly prescribed to patients with systemic lupus erythematosus, nephrotic syndrome, or organ transplantation, are a leading cause of femoral head osteonecrosis; this is known as steroid-associated osteonecrosis [1,35,41]. Once osteonecrosis begins, 80% of femoral heads will collapse if no treatment is administered [32]. Steroid-associated osteonecrosis can lead to social and family burdens, especially because these patients often are young.…”