This study investigates whether PMS can directly promote fracture healing by improving bone tissue formation and structural integrity, as evaluated in a controlled mouse model.
Ninety-six 12-week-old male mice were divided into following four groups: control group, and 10 Hz, 50 Hz, or 100 Hz PMS treatment groups. Starting the day after inducing fractures in the femoral diaphysis, the PMS groups received daily 30-minute interventions. Pain levels were assessed weekly using the von Frey test, while bone healing was evaluated using μCT imaging, histological analysis, and mechanical testing after a 4-week period.
The 10 Hz group showed a significantly higher pain threshold at several time points than that of the control group, while the 100 Hz group exhibited a significant increase at 4 weeks post-intervention. μCT analysis showed increased bone volume in the 100 Hz group at 1 week post-intervention and in the 10 Hz group at 2 weeks, followed by a reduction in bone volume in the 10 Hz group at 3 weeks. By 4 weeks, there were no significant differences in bone volume among all groups. However, the mechanical strength of the 10 Hz group was significantly greater than that of the control group at 4 weeks, as indicated by the higher maximal load and fracture energy. Histological analysis (Safranin O/Fast green) revealed that, at 14 days post-fracture, the 10 Hz group had a higher degree of fracture healing according to the Allen grading system compared to the control. Notably, PMS had no impact on the overall pseudo-bone area at any time point. On day 7 post-fracture, the 10 Hz and 100 Hz groups showed significantly more cartilage formation than that of the control group. Additionally, both the 10 Hz and 100 Hz groups promoted new bone formation in the fracture site at day 14, followed by a decrease in new bone formation by day 21. when compared to the control and 50 Hz groups. Picrosirius red/Alcian blue staining further confirmed that PMS had no effect on the pseudo-bone area, while the fibrous tissue area (including new bone and non-cartilage tissue) on day 7 was relatively reduced in the treatment groups as compared to the control group.
PMS at 10 Hz and 100 Hz effectively reduces pain and enhances bone healing in this mouse model. Our findings suggest that PMS could be a promising non-invasive treatment for fractures.
This study highlights the potential of PMS to advance bone healing and suggests a new direction for non-invasive fracture treatment strategies.
bone fracture healing
rehabilitation
