MANF Alleviates Sevoflurane-Induced Cognitive Impairment in Neonatal Mice by Modulating Microglial Activation and Polarization.

The precise mechanism underlying sevoflurane-induced neurotoxicity and cognitive impairment remains largely unknown. Mesencephalic astrocyte-derived neurotrophic factor (MANF) is a neuroprotective factor that has shown promise in various neurological disorders. However, its impact on sevoflurane-induced alterations has not been investigated. Thus, the objective of this study was to examine the effect of MANF in mitigating sevoflurane-induced neurotoxicity in young mice. Anesthesia with 3% sevoflurane 2 h daily was administered to young mice on postnatal day (P) 3, 6 and 9. We also constructed mono-macrophage-specific MANF knockout (MKO) mice in the mechanistic studies. Finally, the recombinant human MANF (rhMANF, 20 μg) protein was intraperitoneally administrated to neonatal mice before the sevoflurane anesthesia and the cognitive function, levels of pro-inflammatory cytokine and synapse-associated protein PSD95, the status of neural apoptosis, microglia activation and oxidative stress in hippocampus of the mice were investigated. The sevoflurane anesthesia increased the expression of endogenous MANF in the hippocampus, especially in microglia. MKO upregulated the expression of tumor necrosis factor-α (TNF-α), accelerated the neural apoptosis and the activation of microglia in hippocampus in young mice. MANF reversed the sevoflurane-induced cognitive impairment and inhibited the upregulation of TNF-α, the neural apoptosis and the reduction of the postsynaptic density protein-95 (PSD95) induced by sevoflurane anesthesia. Also, pretreatment with MANF alleviated the sevoflurane-induced activation of microglia and oxidative stress. Our current results demonstrated that MANF ameliorated neurotoxicity induced by the sevoflurane anesthesia in young mice, and such protective effect was associated with inhibition of microglia activation and neuroinflammation.