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management of patients with severe TBI. The core task human iPSCs. The choice of the CCI model in this study
of neuro-intensive care is to assess the physiological state is based on its ability to precisely control the degree of
within the patient’s brain in real-time through various injury, simulate real TBI, and provide high reproducibility
monitoring methods (such as intracranial pressure and standardization. The CCI model allows for precise
monitoring, brain oxygen monitoring, and brain metabolic simulation of localized cortical injuries commonly seen
monitoring) and to take timely intervention measures in human TBI by adjusting parameters such as impactor
to halt the progression of secondary injury. The current velocity, depth, and duration. This makes it particularly
research and clinical practice indicate that the treatment suitable for studying post-injury pathological changes
of severe TBI relies not only on emergency surgical and neuroprotective strategies. Compared to the fluid
intervention but also on interdisciplinary collaboration for percussion injury (FPI) model, the CCI model has an
comprehensive treatment. advantage in simulating localized cortical injuries, while
the FPI model is more appropriate for studying diffuse
3.2. Construction strategies of organoids in TBI brain injuries. In addition, compared to the weight-drop
3.2.1. Traditional models and organoids in TBI model, the CCI model offers superior precision and
research reproducibility in controlling injury, making it a better
choice for studying pathological mechanisms and potential
Traditional in vitro models (such as 2D cell cultures) can
provide pathological information but lack 3D structure and therapeutic strategies. Therefore, the CCI model provides
unique advantages in simulating localized cortical injuries
cell–cell interactions; animal models excel in simulating
biophysical features post-TBI (e.g., neuronal damage, in TBI and serves as an ideal tool for investigating TBI
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astrocyte proliferation, and apoptosis), yet they cannot pathophysiology and potential therapeutic approaches.
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fully replicate the complexity and cellular diversity of the After CCI treatment, researchers analyzed neurons and
human brain. Organoid models, with their human genetic astrocytes in cerebral organoids using microtubule-
background, are considered a promising platform for more associated protein 2 and glial fibrillary acidic protein
accurately simulating the human brain’s response to injury. (GFAP) as markers. They also assessed metabolic response
Early in vitro models simulated axonal transection through markers (e.g., neuron-specific enolase, NSE) and cell death
compression or hydrostatic pressure, but static models markers (e.g., cleaved caspase) to quantify neuronal damage
failed to reflect the complex mechanical stress conditions in and apoptosis. The study showed that human cerebral
TBI. 64,65 Dynamic mechanical injury models, using rotating organoids in this TBI model effectively reproduced key
disks or micropipettes to apply fluid shear forces or culturing pathological features of TBI, including metabolic changes,
neurons on flexible membranes for controlled stretch neuronal loss, and reactive astrogliosis, demonstrating its
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injuries, better mimic the actual mechanical environment ability to simulate critical TBI processes.
of TBI. Engineered neural tissues (e.g., neuron systems 3.2.2.2. cBOS model
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embedded in hydrogels or polymer scaffolds) incorporate
human cells for their 3D structures and physiological Long-term cultured BOs often develop a hypoxic necrotic
conditions they can afford, 67,68 though they still fall short in core due to their complex 3D structure, which affects the
replicating the full complexity of brain tissue. stability and accuracy of experimental results. To address
this issue, cortical BO slices (cBOS) provide a viable
3.2.2. Construction strategies for organoid models alternative for studying the function and networks of neural
in TBI cells within complex 3D structures. By slicing BOs and
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The organoid model must reproduce TBI’s pathological culturing them at the air-liquid interface, the formation of
features and closely mimic human pathology. The current necrotic cores can be effectively avoided while maintaining
organoids subjected to controlled cortical impact (CCI) the tissue’s 3D structure and cellular microenvironment.
replicate key TBI features, including neuronal damage, Petersilie et al. developed a method for preparing cBOS,
loss, and astrocytosis. In addition, stretch injury or which is based on regionalized cortical organoids and
axonal transection experiments reveal neuronal calcium involves culturing slices at the air-liquid interface, making
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signaling changes, cytoskeletal damage, and neuronal them easier to maintain long-term.
death, mirroring the DAI observed in TBI patients. 51,65,66,69,70 Compared to traditional whole-BOs, cBOS exhibit
These organoid-based TBI models provide robust tools for significantly reduced heterogeneity and are more robust in
elucidating brain injury mechanisms. terms of morphology and function. As a result, cBOS provide
an ideal starting point for generating homogeneously
3.2.2.1. CCI model cultured neural tissues. This platform offers researchers
The CCI model is an innovative in vitro TBI model various experimental approaches to probe neuronal
established by researchers using BOs derived from function and dysfunction, such as electrophysiological

Volume 1 Issue 1 (2025) 5 doi: 10.36922/or.8261