Shockwaves enhance the osteogenetic gene expression in marrow stromal cells from hips with osteonecrosis.

Background: This in vitro study investigated the angiogenesis and osteogenesis effects of shockwaves on bone marrow stromal cells (BMSCs) from hips with osteonecrosis.

Methods: BMSCs were harvested from the bone marrow cavity of the proximal femur in six patients with osteonecrosis of the femoral head. The specimens were divided into four groups, the control, shockwave, shockwave plus nω-nitro- L-arginine methyl ester (L-NAME) and a nitric oxide (NO) donor (NOC18) groups. The control group received no shockwaves and was used as the baseline. The shockwave group received 250 shockwave impulses at 14 Kv (equivalent to 0.18 mJ/mm2 energy flux density). The shockwave plus LNAME group was pre-treated with L-NAME before receiving shockwaves. The NOC18 group received NOC18 after cell culture for 48 hours. The evaluations included cell proliferation (MTT) assay, alkaline phosphatase, real time reverse transcriptase-polymerase chain reaction analysis of vessel endothelial growth factor (VEGF), bone morphogenic protein (BMP)-2, RUNX2 and osteocalcin mRNA expression and von Kossa stain for mineralized nodules.

Results: The shockwave group showed significant increases in MTT, VEGF, alkaline phosphatase, BMP2, RUNX2 and osteocalcin mRNA expression and more mature mineralized nodules compared with the control. Pre-treatment with L-NAME significantly reduced the angiogenic and osteogenic effects of extracorporeal shockwave therapy (ESWT) and the results were comparable with the control. Administration of NOC18 significantly enhanced the angiogenesis and osteogenesis effects compared with the control and the results were comparable with the shockwave group.

Conclusion: ESWT significantly enhanced the angiogenic and osteogenic effects of BMSCs mediated through the NO pathway in hips with osteonecrosis. These innovative findings, at least in part, explain some of the mechanism of shockwaves in osteonecrosis of the hip.