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Comparative study of acute-phase traumatic brain injury in rats of different weeks of age under identical impact force

Year: 2026

Type: article

Abstract: The closed head injury (CHI) model in rats is widely used in preclinical research, yet this model exhibits certain variability, partly due to the use of rats of different ages in experiments. To explore this variability, we selected rats of commonly used ages (8, 10, and 12 weeks) and induced brain injury under the same impact strength, comparing biomechanical responses, behavioral changes, and neuropathological outcomes. The results indicated that with increasing age, linear acceleration and rotational acceleration significantly decreased, and the younger age group (8 weeks) exhibited more severe neurological deficits and behavioral impairments, particularly in motor coordination and anxiety-like behaviors. Histological analysis showed the most severe neuronal loss and disorganization in the cerebral cortex and hippocampus in the 8-week group, with more extensive axonal injury. In contrast, the 10-week and 12-week groups showed milder pathological changes and better-preserved neuronal morphology. Molecular analysis revealed higher expression levels of glial fibrillary acidic protein, cleaved caspase-3, and interleukin-1 beta in younger rats, suggesting a positive correlation between these molecular markers and injury severity. Overall, this study reveals the significant impact of age differences in rats on TBI outcomes, highlighting the importance of age in TBI experiments and providing a basis for reducing experimental variability and enhancing the translational relevance to clinical applications.

Source: Frontiers in Neurology

DOI: 10.3389/fneur.2026.1928195