N-Acety-L-Cysteine Alleviates Isoflurane-Triggered Neuronal Cell Parthanatos by Suppressing Reactive Oxygen Species Accumulation Through the Induction of c-Jun N-Terminal Kinase Signaling Pathway Inhibition

In recent years, the potential neurotoxicity of inhaled anesthetics on the developing brain has increasingly garnered attention, yet its mechanism remains unclear. Parthanatos is a newly discovered form of programmed cell death dependent on PARP-1, and it is believed to be closely associated with cellular oxidative stress response. However, it is still to be proven whether isoflurane, a commonly used clinical anesthetic, can induce parthanatos in developing brain neurons and whether it activates the oxidative stress signaling pathway in neuronal cells. In this study, we treated SH-SY5Y cells and rat hippocampus neuron cells (RN-h) with isoflurane, measured cell viability using the MTT assay, examined the activation of the parthanatos-related PARP-1/AIF/PAR signaling pathway using western blot analysis, detected the accumulation of ROS using DCFH-DA, detected mitochondrial membrane potential (Δψm) by a JC-1 assay, and assessed the activation of the oxidative stress-related JNK signaling pathway using western blot. In vivo, we examined the damaging effects of inhaled isoflurane on neonatal rat hippocampal neurons using HE staining. The results showed that 2% and 4% concentrations of isoflurane significantly inhibited cell survival and upregulated the expression levels of PARP-1, AIF, and PAR in both types of neuronal cells. Moreover, isoflurane significantly enhanced ROS levels and decreased Δψm, and activated the JNK signaling pathway in both cell types. Importantly, we found that pretreatment with N-Acetylcysteine (NAC) could inhibit isoflurane-induced parthanatos and the accumulation of ROS in cells, as well as the activation of the JNK pathway. The experimental results in neonatal rats also demonstrated that isoflurane led to significant neuronal death in the hippocampal CA1 region. However, pretreatment with NAC significantly increased the survival rate of pyramidal neurons in this region. In summary, through our experiments, we confirmed that isoflurane can induce parthanatos in neuronal cells, and NAC can decrease ROS accumulation in neuronal cells and thus mitigate the damage isoflurane causes to neuronal cells.