Prophylactic treatment of hyperbaric oxygen treatment mitigates inflammatory response via mitochondria transfer

Abstract

AIMS: Hyperbaric oxygen therapy (HBOT) has been widely used as postinjury treatment; however, we investigate its ability to mitigate potential damage as a preconditioning option. Here, we tested the hypothesis that HBOT preconditioning mitigates cell death in primary rat neuronal cells (PRNCs) through the transfer of mitochondria from astrocytes. METHODS: Primary rat neuronal cells were subjected to a 90-minute HBOT treatment at 2.5 absolute atmospheres prior to either tumor necrosis factor-alpha (TNF-alpha) or lipopolysaccharide (LPS) injury to simulate the inflammation-plagued secondary cell death associated with stroke and traumatic brain injury (TBI). After incubation with TNF-alpha or LPS, the cell viability of each group was examined. RESULTS: There was a significant increase of cell viability accompanied by mitochondrial transfer in the injury groups that received HBOT preconditioning compared to the injury alone groups (44 ± 5.2 vs 68 ± 4.48, n = 20, P < 0.05). The transfer of mitochondria directly after HBOT treatment was visualized by capturing images in 5-minute intervals, which revealed that the robust transfer of mitochondria begins soon after HBOT and persisted throughout the treatment. CONCLUSION: This study shows that HBOT preconditioning stands as a robust prophylactic treatment for sequestration of inflammation inherent in stroke and TBI, possibly facilitating the transfer of resilient mitochondria from astrocytes to inflammation-susceptible neuronal cells in mitigating cell death.