CORM-3 improves emotional changes induced by hemorrhagic shock via the inhibition of pyroptosis in the amygdala

Hemorrhagic shock and resuscitation (HSR) may lead to long-term neurological dysfunction, such as depression and anxiety. Carbon monoxide (CO) has emerged as an excellent neuroprotective agent against caspase-1-associated pyroptosis, following HSR. We evaluated the effects and determined the mechanism through which CO protects against emotional changes in a model of HSR, in rats. We subjected rats to treatments with an exogenous, CO-releasing compound (CORM-3, 4 mg/kg), in vivo, after HSR. We measured sucrose preference and performed tail suspension and open field tests 7 days after HSR, assessed brain magnetic resonance imaging 12 h after HSR and evaluated pyroptosis, and neuronal and astrocyte death in the amygdala 12 h post-HSR. We also measured changes in behavior and pathology, following an injection of recombinant murine interleukin (IL)-18 into the amygdala. HSR-treated rats displayed increased depression-like and anxiety-like behaviors, increased amygdalar injury, as indicated by T2-weighted magnetic resonance imaging (MRI) and cerebral blood flow with arterial spin labeling (CBFASL), associated with both neuronal and astrocytic death and pyroptosis, and upregulated IL-18 expression was observed in astrocytes. CORM-3 administration after resuscitation, via a femoral vein injection, provided neuroprotection against HSR, and this neuroprotective effect could be partially reversed by the injection of recombinant murine IL-18 into the amygdala. Therefore, CORM-3 alleviated HSR-induced neuronal pyroptosis and emotional changes, through the downregulation of IL-18 in astrocytes.