Aberrant spinal mechanical loading stress triggers intervertebral disc degeneration by inducing pyroptosis and nerve ingrowth

Abstract

Aberrant mechanical factor is one of the etiologies of the intervertebral disc (IVD) degeneration (IVDD). However, the exact molecular mechanism of spinal mechanical loading stress-induced IVDD has yet to be elucidated due to a lack of an ideal and stable IVDD animal model. The present study aimed to establish a stable IVDD mouse model and evaluated the effect of aberrant spinal mechanical loading on the pathogenesis of IVDD. Eight-week-old male mice were treated with lumbar spine instability (LSI) surgery to induce IVDD. The progression of IVDD was evaluated by μCT and Safranin O/Fast green staining analysis. The metabolism of extracellular matrix, ingrowth of sensory nerves, pyroptosis in IVDs tissues were determined by immunohistological or real-time PCR analysis. The apoptosis of IVD cells was tested by TUNEL assay. IVDD modeling was successfully produced by LSI surgery, with substantial reductions in IVD height, BS/TV, Tb.N. and lower IVD score. LSI administration led to the histologic change of disc degeneration, disruption of the matrix metabolism, promotion of apoptosis of IVD cells and invasion of sensory nerves into annulus fibrosus, as well as induction of pyroptosis. Moreover, LSI surgery activated Wnt signaling in IVD tissues. Mechanical instability caused by LSI surgery accelerates the disc matrix degradation, nerve invasion, pyroptosis, and eventually lead to IVDD, which provided an alternative mouse IVDD model.

Comprehensive analysis of N6-methyladenosine (m6A) modification during the degeneration of lumbar intervertebral disc in mice

“…LBP caused by IDD has become an important factor affecting the quality of life of modern people, resulting in disability in millions of people every year and imposing a huge economic burden on families, society and the medical system [ 2 ]. The etiologies of IDD are diverse, including smoking [ 7 ], high mechanical stress [ 8 , 9 ], sex [ 10 ], and age [ 11 ], but the specific cellular and molecular mechanisms involved are still unclear. Related bio-mechanical changes are considered to be one of the important factors leading to IDD because they can change the cell metabolism of the IVD [ 41 ].…”

“…IDD often leads to annulus fibrosus (AF) rupture, and NP herniation and stimulates or compresses nerve roots or the cauda equina, with corresponding clinical symptoms. There are various reasons for IDD, including smoking [ 7 ], high mechanical stress [ 8 , 9 ], sex [ 10 ], and age [ 11 ], but the exact cellular and molecular mechanisms are still unclear. The NP is one of the components of the intervertebral disc (IVD).…”

Increased Calcitonin Gene-Related Peptide Expression in DRG and Nerve Fibers Proliferation Caused by Nonunion Fracture in Rats

“…Recent study report that aberrant mechanical stress induces sensory nerve invasion degenerated intervertebral disc in mouse. 23 The study consists with our results that aberrant instability induced abnormal nerve proliferation.…”

Network Pharmacology and Experimental Validation to Reveal the Pharmacological Mechanisms of Liuwei Dihuang Decoction Against Intervertebral Disc Degeneration

“…IVDD model was established by lumbar spine instability (LSI)-surgery as we previously reported. 28 Briefly, the mice were anesthetized with 1.5% isoflurane (R510-22-16, RWD Life Science, Shenzhen, China) in 100% oxygen flowing at 1.0 L/min and placed on the surgical table in a prone position. Then, a 2 cm longitudinal incision was made along the midline of the back to expose the lumbar 3rd–5th spinous processes.…”

“…The lumbar tissues were processed into 5-μm-thick coronal-oriented sections and stained with hematoxylin–eosin (H&E). 28 For IF assay, sections were incubated with primary antibodies of Aggrecan (diluted 1:300), Col-II (diluted 1:500), Mmp3 (diluted 1:300), Adamts5 (diluted 1:300), Bcl-2 (diluted 1:300), Bax (diluted 1:300), Caspase-3 (diluted 1:300), P53 (diluted 1:500), IL-1β (diluted 1:500) at 4°C overnight. For IHC analysis, secondary biotinylated goat anti-rabbit antibody (diluted 1:1000) (Invitrogen) was added for 30 min the following day.…”