Photobiomodulation in the Treatment of Acute Traumatic Brain Injury

Introduction: Traumatic brain injury (TBI) results in enduring brain damage and cognitive impairments, often progressing to neurodegenerative conditions. The brain drainage system plays a pivotal role in TBI recovery and mitigating neurodegenerative diseases by eliminating waste macromolecules from the brain. However, conventional pharmacological treatments have not shown significant benefits in human TBI cases. Photobiomodulation (PBM) has emerged as a promising intervention in neuroscience, demonstrating the potential to enhance brain drainage. Herein, we aimed to assess the efficacy of PBM in treating TBI using a mouse model of closed-head contusion.


Methods: Closed-head contusional TBI was induced in the left hemisphere, focusing on the prefrontal cortex of C57BL/6 wild-type mice. PBM was administered using near-infrared irradiation (1270 nm, 10 mW/cm²) four hours after the TBI and continued twice daily for the following three days. In-vivo 2-photon laser scanning microscopy was employed to evaluate the effects of PBM on cerebral microcirculation, hypoxia, blood-brain barrier (BBB) integrity, and glymphatic/meningeal lymphatic clearance. Neurological severity scores were evaluated at 24 hours and 1 and 2 weeks post-TBI. Intergroup differences were analyzed using two-way ANOVA for multiple comparisons, with statistical significance set at p< 0.05.


Results: TBI led to a progressive decline in cortical microcirculation, tissue hypoxia, BBB disruption, and impairment of brain drainage function (p < 0.05). PBM significantly ameliorated microcirculation and tissue oxygenation while safeguarding BBB integrity and brain drainage compared to the sham-treated group (p < 0.05). Furthermore, neurological function was better preserved in the PBM group compared to the sham-treated mice (p < 0.05).


Conclusions: PBM administered during the acute phase following TBI effectively restored cerebral microcirculation and brain drainage, thereby reducing tissue hypoxia and BBB damage, ultimately improving neurological outcomes. PBM emerges as a promising adjunctive therapy, even when initiated during the acute phase of TBI.