Whole-body Vibration Attenuates Pyroptosis-Mediated Inflammation but Accelerates Progression of Intervertebral Disc Degeneration

Background Whole body vibration (WBV) is a non-pharmaceutical therapy that has been widely incorporated into clinical practice for musculoskeletal disorders, including low back pain (LBP). Intervertebral disc (IVD) degeneration (IVDD) is clinically associated with LBP and is known as the main cause for LBP. However, cumulative evidence also suggested WBV might have an adverse impact on IVDs. Moreover, previous studies have been focusing on the effects of WBV on healthy mice, rather than those suffering from IVDD. Thus, uncertainties still exist concerning the effects of WBV on IVDs undergoing IVDD. This study was aiming to evaluate the effects of WBV intervention on the development and progression of IVDD mouse model induced by lumbar spine instability (LSI) surgery. Methods LSI surgery, by resecting the lumbar 3 rd -5 th spinous processes along with the supraspinous and interspinous ligaments, was conducted in 10-week-old male mice which then received WBV treatment (1 h per day, 5 days per week, at 3 Hz with peak acceleration at 0.4 g) or sham treatment. The progression of IVDD was evaluated by MRI, μCT and histological analyses after WBV treatment. The matrix metabolism, distribution of sensory nerves, pyroptosis in IVDs tissues were determined by immunohistological analysis or real-time PCR. The apoptosis of IVD cells was detected by TUNEL assay. Results LSI surgery was successful in producing IVDD modeling. WBV caused decreases in IVD height and annulus fibrosus (AF) score, as well as increased numbers of apoptotic cells in IVD tissues. WBV contributed to sensory innervation into AF and upregulation of Adamts5 and MMP3 expression in IVDD mice received LSI surgery. In addition, WBV treatment triggered earlier activation of Wnt/β-catenin signaling in IVDD mice with WBV treatment compared with those without WBV treatment. Unexpectedly, WBV significantly attenuated Caspase-1 and IL-1β expression in AF. Conclusions Collectively, our findings demonstrate that WBV treatment may worsen the development of ongoing IVDD. Decrease of IL-1β expression after WBV intervention may partially account for patient self-reported pain relief after WBV treatment in some previous trials. This study may help us better understand the effects of WBV intervention on patients experiencing LBP resulting from the degeneration of lumbar IVDs.