椎間盤髓核細胞退化的力學模型與治療可行性探討

Abstract

椎間盤的髓核退化經常伴隨著髓核細胞的形態改變，過度的機械負載被認為是導致這種現象的關鍵因素。為了更了解機械應力對於髓核細胞的影響，過去實驗室建立了三維培養之髓核細胞水膠穿刺模型，發現接近穿刺邊緣的髓核細胞核會受應力影響而拉長。基於這個現象，本研究欲探討髓核細胞核拉長現象由何種機械力敏感通道調控，並確認細胞核拉長現象所代表的生理意義。此外，本研究欲了解超音波介導的壓電刺激是否能夠逆轉髓核細胞核受力拉長之現象。最後，本研究欲建立小鼠體內的椎間盤退化模型，作為探討治療可行性的基礎。 本研究的結果表明，透過抑制ASIC3通道能夠抑制細胞核沿切線方向拉長之現象，然而抑制TRP4通道與Piezo1通道皆無法抑制此現象。此外，水膠穿刺模型中的細胞YAP螢光強度下降，且YAP定位在細胞核的比例亦下降。此現象將可能導致YAP下游與細胞修復相關的蛋白無法被轉譯。本研究還發現了微能量脈衝超音波介導之壓電刺激具有逆轉穿刺模型中髓核細胞核的拉長，且此現象不是由纖毛極性所調控。最後，本研究建立了鼠尾環椎間盤退化模型，此模型能用來探討超音波與壓電刺激對於椎間盤退化的治療可行性。總的來說，本研究有助於人們對於髓核細胞受力後的力生物學反應以及治療可行性有進一步的了解。

The degeneration of nucleus pulposus (NP) is often accompanied by morphological changes in NP cells, with excessive mechanical loading believed to be a key factor contributing to this phenomenon. To better understand the effect of mechanical stress on NP cells, the previous study in our lab established a three-dimensional hydrogel punctured model for NP cells culture, revealing that NP cells nuclei near the puncture edge elongate under stress. Based on this observation, this study aims to investigate which mechanosensitive channels regulate the elongation of NP cells nuclei and to determine the physiological significance of this elongation. Additionally, this study seeks to understand whether ultrasound-mediated piezoelectric stimulation can reverse the elongation of NP cells nuclei under stress. Finally, this study aims to establish an in vivo mouse model of intervertebral disc degeneration to explore the feasibility of potential treatments.

The results of this study indicate that inhibiting the ASIC3 channel can prevent the elongation of NP cells nucleus, whereas inhibiting the TRP4 and Piezo1 channels does not have this effect. Furthermore, the fluorescent intensity of YAP in cells within the hydrogel punctured model decreased. This phenomenon may lead to the failure of YAP downstream proteins associated with cell repair to be translated. The study also found that low-intensity pulsed ultrasound-mediated piezoelectric stimulation can reverse the elongation of NP cells nuclei in the puncture model, and this effect is not regulated by ciliary orientation. Lastly, a mouse tail-looping model was established, which can be used to investigate the therapeutic potential of ultrasound and piezoelectric stimulation for disc degeneration. Overall, this study contributes to a deeper understanding of the mechanobiological responses of NP cells to mechanical stress and the feasibility of potential treatments.