Protective effects of hydrogen gas against spinal cord ischemia-reperfusion injury

Objective: This experimental study aimed to assess the efficacy of hydrogen gas inhalation against spinal cord ischemia-reperfusion injury and reveal its mechanism by measuring glutamate concentration in the ventral horn using an in vivo microdialysis method. Methods: Male Sprague-Dawley rats were divided into the following 6 groups: sham, only spinal ischemia, 3% hydrogen gas (spinal ischemia thorn 3% hydrogen gas), 2% hydrogen gas (spinal ischemia thorn 2% hydrogen gas), 1% hydrogen gas (spinal ischemia thorn 1% hydrogen gas), and hydrogen gas dihydrokainate (spinal ischemia thorn dihydrokainate [selective inhibitor of glutamate transporter-1] thorn 3% hydrogen gas). Hydrogen gas inhalation was initiated 10 minutes before the ischemia. For the hydrogen gas dihydrokainate group, glutamate transporter-1 inhibitor was administered 20 minutes before the ischemia. Immunofluorescence was performed to assess the expression of glutamate transporter-1 in the ventral horn. Results: The increase in extracellular glutamate induced by spinal ischemia was significantly suppressed by 3% hydrogen gas inhalation (P<.05). This effect was produced in increasing order: 1%, 2%, and 3%. Conversely, the preadministration of glutamate transporter-1 inhibitor diminished the suppression of spinal ischemia-induced glutamate increase observed during the inhalation of 3% hydrogen gas. Immunofluorescence indicated the expression of glutamate transporter-1 in the spinal ischemia group was significantly decreased compared with the sham group, which was attenuated by 3% hydrogen gas inhalation (P<.05). Conclusions: Our study demonstrated hydrogen gas inhalation exhibits a protective and concentration-dependent effect against spinal ischemic injury, and glutamate transporter-1 has an important role in the protective effects against spinal cord injury.