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models further allow direct assessment of reconstruction serve as an alternative system for simulating complex
techniques and biomaterial integration. 84-86 Despite their tissue functions but also provide an ideal platform for
utility, these models face limitations, including interspecies gaining more intuitive and in-depth insights into disease
variability, difficulty in replicating human biomechanical pathogenesis and treatment (Table 1). Therefore, a
environments, and ethical concerns. comprehensive understanding of recent advances in MSK
2.5. Neurological dysfunction-related animal models organoid research is crucial for their future development,
refinement, and translational application.
2.5.1. SCI animal models
The development of MSK organoid technology has
Spinal cord contusion-induced limb motor dysfunction undergone a critical evolution from single-tissue modeling
represents severe orthopedic diseases with a high to multi-system integration. Research on MSK organoids
morbidity and disability rate. Various animal models of SCI can be traced back to as early as 1990, when Zimmermann
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effectively assess post-injury MSK alterations. Traumatic et al. developed a cartilage organoid culture to study
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injury models predominate, with controlled contusion endochondral mineralization. Subsequently, Sass
devices replicating clinical spinal cord contusions. 88-90 et al. applied limb bud mesenchymal cell organoids to
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Complete/partial transection models enable axonal drug screening for evaluating the teratogenic potency of
regeneration studies, 91,92 while distraction injuries model retinoids. In the early 2000s, Vandenburgh et al. utilized
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vehicular trauma. These reliably reproduce hallmarks primitive embryonic avian or neonatal rodent myoblasts
of traumatic SCI, including hemorrhage, edema, and to create uniformly batch-producible muscle organoids,
neuroinflammation. Ischemic injury models, induced advancing the technology toward practical applications.
through vascular occlusion or photochemical techniques, As single-structure organoid techniques matured, research
exhibit distinct pathophysiology. 94-97 Compression models focus shifted to multi-structure integrated organoids.
simulate disc herniation or hematoma effects, particularly Muraglia et al. formed chondro-osseous organoids
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valuable for myelopathy research. Chemical models using through bone marrow stromal cells, while Mizuno
targeted neurotoxins permit focused investigation of et al. developed spherical organoids with depth-specific
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apoptosis and demyelination mechanisms. 98-101 architecture, longitudinal depth zones in articular cartilage.
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2.5.2. Peripheral nerve injury models By 2020, Hall et al. proposed the “callus organoid”
concept to predict long bone healing mechanisms, followed
Peripheral nerve injury animal models are crucial by Akiva et al. in 2021, constructing a 3D self-organizing
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for investigating nerve damage-induced MSK system co-culture of osteoblasts and osteocytes for early-stage
dysfunction. 102 Crush injury models, including woven bone formation, establishing the most complete 3D
standardized forceps compression and chronic living in vitro model system. Dai et al. further engineered
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constriction, effectively simulate clinical nerve entrapment in vivo osteo-organoids using bone morphogenetic
syndromes and chronic neuropathies while preserving protein (BMP)-2-loaded scaffolds, pioneering novel osteo-
epineurial integrity, facilitating the study of Wallerian organoid-derived cell therapeutic strategies. In pathological
degeneration and axonal regeneration processes. 103-105 modeling, Hu et al. established bone metastasis organoids
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Transection models are classified by injury completeness, from lung adenocarcinoma to validate denosumab efficacy.
with complete transection enabling nerve graft evaluation Recently, Yin et al. generated self-organized human
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and partial transection permitting study of spontaneous neuromusculoskeletal organoids (hNMSOs), achieving
regeneration. 106-108 Chemical models utilized neurotoxic cross-tissue functional regulation through neuromuscular
agents for selective fiber-type damage or ethanol for focal junctions (NMJs) and marking an unprecedented level of
demyelination, though they require a carefully optimized technological sophistication. The rapid advancement of
dose due to potential systemic toxicity. 109-111 organoid technology has made it increasingly feasible for
organoids to replace animal experiments (Figure 2).
3. Advances in MSK organoids
With the rapid advancement of organoid technology 3.1. Bone organoids
and growing ethical and scientific imperatives to reduce Bone organoids refer to 3D, miniaturized, and simplified
reliance on animal models, MSK organoids have emerged bone tissues generated in vitro using stem cells or progenitor
as a transformative tool in regenerative medicine. These cells, aiming to mimic the structure, function, and
3D, multicellular constructs recapitulate key structural intercellular communication of natural bone tissue. They
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and functional features of native bone, cartilage, and consist of various cell types, including bone mesenchymal
muscle tissues, offering unprecedented opportunities stem cells (BMSCs), osteoblasts, osteoclasts, and mature
to study developmental biology, disease mechanisms, osteocytes, and undergo a mineralization process to form
and therapeutic interventions. MSK organoids not only a rigid, bone-like matrix. Current research in bone
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Volume 1 Issue 3 (2025) 5 doi: 10.36922/OR025280024