硬式 PZT 與軟式 PVDF 壓電探頭對退化椎間盤 細胞外基質與發炎反應之影響

Abstract

椎間盤退化（Intervertebral Disc Degeneration, IDD）是造成下背痛的主要原因之一，目前治療方式多僅能暫時緩解症狀，難以促進組織再生，且部分侵入性療法可能進一步破壞椎間盤結構。研究顯示，椎間盤具壓電特性，在機械刺激下可產生局部電場，進而調控細胞行為與組織修復。

本研究建立小鼠尾椎椎間盤退化模型，並比較以硬式 PZT 與軟式 PVDF 壓電材料製成探頭進行低強度脈衝超音波（ISATA：33 mW/cm²）治療兩週之效果。實驗結果顯示，PVDF 探頭相較於 PZT 探頭能更有效抑制 TNF-α 與 IL-1β 的發炎表現，並在 ECM 組成方面提升 Collagen II 與 Aggrecan 表現，降低 Collagen I，尤以纖維環區恢復幅度最為明顯。

細胞實驗部分，建立含 RGD 的水凝膠三維髓核細胞培養系統，種植於石英（具壓電性）與玻璃（不具壓電性）片上，並搭配酸敏感通道（ASIC）抑制劑，探討超音波介導壓電刺激之機械反應。結果顯示，細胞核形態延展性整體變化不顯著，可能因本研究條件下細胞對形態指標較不敏感，需進一步優化觀察參數。

本研究結果提供低能量超音波與壓電材料應用於椎間盤修復之初步依據，並顯示 PVDF 具更佳生物相容性與刺激效率，具有非侵入性治療應用潛力。

Intervertebral disc degeneration (IDD) is a major cause of low back pain. Most current treatments only offer temporary relief and cannot repair damaged disc tissue. Some invasive procedures may even worsen the disc structure. Studies suggest that discs possess piezoelectric properties, generating local electric fields under mechanical stress that may support cell function and tissue repair.

In this study, we used a mouse tail model of disc degeneration and applied low-intensity pulsed ultrasound (ISATA: 33 mW/cm²) for two weeks using two types of piezoelectric materials: rigid PZT and flexible PVDF. Results showed that the PVDF probe was better than the PZT probe at reducing inflammation (TNF-α and IL-1β) and improving the expression of ECM proteins like Collagen II and Aggrecan, while lowering Collagen I. The improvement was most noticeable in the annulus fibrosus area.

In cell experiments, we created a 3D culture system using hydrogels with RGD peptides and seeded nucleus pulposus cells on quartz (piezoelectric) and glass (non-piezoelectric) surfaces. We also used an ASIC inhibitor to study how cells respond to piezoelectric ultrasound. The results showed only slight changes in nuclear shape, with no significant differences, suggesting that under these conditions, cells may not be very sensitive to the stimulus, or longer testing may be needed.

Overall, this study shows that low-intensity ultrasound combined with PVDF piezoelectric material has good potential for helping repair degenerated discs in a non-invasive way.