Early cerebrovascular and long-term neurological modifications ensue following juvenile mild traumatic brain injury in male mice

https://doi.org/10.1016/j.nbd.2020.104952Get rights and content
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Highlights

  • Juvenile mild TBI provokes an early and transient cerebrovascular hypo‑oxygenation in vivo.

  • Cerebrovascular reactivity is modified in brain slices derived from juvenile mild TBI mice.

  • Juvenile mild TBI induces changes in cortical vessel morphology.

  • Video-EEG exploration indicates long-term modifications of gamma waves distribution in the impacted cortical region .

Abstract

Clinical evidence suggests that a mild traumatic brain injury occurring at a juvenile age (jmTBI) may be sufficient to elicit pathophysiological modifications. However, clinical reports are not adequately integrated with experimental studies examining brain changes occurring post-jmTBI. We monitored the cerebrovascular modifications and assessed the long-term behavioral and electrographic changes resulting from experimental jmTBI.

In vivo photoacoustic imaging demonstrated a decrease of cerebrovascular oxygen saturation levels in the impacted area hours post-jmTBI. Three days post-jmTBI oxygenation returned to pre-jmTBI levels, stabilizing at 7 and 30 days after the injury. At the functional level, cortical arterioles displayed no NMDA vasodilation response, while vasoconstriction induced by thromboxane receptor agonist was enhanced at 1 day post-jmTBI. Arterioles showed abnormal NMDA vasodilation at 3 days post-jmTBI, returning to normality at 7 days post injury. Histology showed changes in vessel diameters from 1 to 30 days post-jmTBI. Neurological evaluation indicated signs of anxiety-like behavior up to 30 days post-jmTBI. EEG recordings performed at the cortical site of impact 30 days post-jmTBI did not indicate seizures activity, although it revealed a reduction of gamma waves as compared to age matched sham. Histology showed decrease of neuronal filament staining. In conclusion, experimental jmTBI triggers an early cerebrovascular hypo‑oxygenation in vivo and faulty vascular reactivity. The exact topographical coherence and the direct casualty between early cerebrovascular changes and the observed long-term neurological modifications remain to be investigated. A potential translational value for cerebro-vascular oxygen monitoring in jmTBI is discussed.

Keywords

Head trauma
Pediatric
Cerebrovascular oxygenation
Blood-brain barrier
Cerebrovascular damage
Vasoreactivity
Neurological sequel

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