Hydrogen-rich saline attenuates isoflurane-induced caspase-3 activation and cognitive impairment via inhibition of isoflurane-induced oxidative stress, mitochondrial dysfunction, and reduction in ATP levels

Abstract

Objectives: The inhaled general anesthetic isoflurane has been shown to induce caspase-3 activation in vitro and in vivo. The underlying mechanisms and functional consequences of this activity remain unclear. Isoflurane can induce caspase-3 activation by causing accumulation of reactive oxygen species (ROS), mitochondrial dysfunction, and reduction in adenosine triphosphate (ATP) levels. This study aimed to investigate the protective effect of hydrogen, a novel antioxidant, against isoflurane-induced caspase-3 activation and cognitive impairment. Methods: H4 human neuroglioma cells overexpressing human amyloid precursor protein were treated with saline or hydrogen-rich saline (HS, 300 μM), with or without 2% isoflurane, for 6 h or 3 h. Western blot analysis, fluorescence assays, and a mitochondrial swelling assay were used to evaluate caspase-3 activation, levels of ROS and ATP, and mitochondrial function. The effect of the interaction of isoflurane (1.4% for 2 h) and HS (5 mL/kg) on cognitive function in mice was also evaluated using a fear conditioning test. Results: We found that HS attenuated isoflurane-induced caspase-3 activation. Moreover, HS treatment mitigated isoflurane-induced ROS accumulation, opening of mitochondrial permeability transition pores, reduction in mitochondrial membrane potential, and reduction in cellular ATP levels. Finally, HS significantly alleviated isoflurane-induced cognitive impairment in mice. Conclusions: Our results suggest that HS attenuates isoflurane-induced caspase-3 activation and cognitive impairment via inhibition of isoflurane-induced oxidative stress, mitochondrial dysfunction, and reduction in ATP levels. These findings warrant further research into the underlying mechanisms of this activity, and indicate that HS has the potential to attenuate anesthesia neurotoxicity.

Study details

Article type

Original Research

Disease / injury model

Isoflurane-induced neurotoxicity and cognitive impairment (Alzheimer's disease-related mechanisms)

Duration

7 days

Dose comparison

The study did not assess dose-dependent effects of hydrogen-rich saline; only a single concentration was used in both in vitro and in vivo experiments.

Dose-dependent effect

No

Outcome

Positive

Findings

Hydrogen-rich saline (HS) attenuates isoflurane-induced caspase-3 activation and cognitive impairment by inhibiting oxidative stress, mitochondrial dysfunction, and ATP reduction in both H4-APP cells and mice.