Effects of Irrigation With Normal Saline on Traumatic Brain Injury Combined With Seawater Immersion in Rats.

Introduction: With the integrated development of the global economy, various economic activities in marine environments are also expanding, along with the number of offshore employees. However, the increased risk of accidental falling and collisions at sea may lead to traumatic brain injury (TBI) accompanied by seawater immersion (SI). The high permeability and alkalinity of seawater increase the risk of TBI and damage to the blood-brain barrier (BBB), which can indirectly result in excessive neuroinflammation, brain edema, and neuronal cell death.

Methods: A well-characterized rat model of TBI + SI induced by controlled cortical impact combined with SI was established. After successful modeling, three different concentrations of sodium chloride (NaCl) solutions were used to irrigate the wound site to assess the effects on rats with early TBI complicated with SI.

Results: The results showed that irrigation with 0.9% NaCl (normal saline [NS]) significantly reduced neurological dysfunction, reduced brain edema, and inhibited neuroinflammatory response in rats with TBI combined with SI. However, irrigation with 3% NaCl (3% hypertonic saline) aggravated the injury, whereas 0.45% NaCl (half-NS) had no obvious improvement. Irrigation with NS can neutralize the high alkalinity of seawater and prevent further damage to the BBB. Irrigation with NS caused fewer morphological changes to the neuronal mitochondria and prevented further damage, suggesting that NS was the most suitable rinse solution.

Conclusions: SI can cause damage to the BBB, neuroinflammation, and neuronal cell death after TBI. Restoration of the injured BBB is a promising strategy for the treatment of TBI combined with SI.