Multiple neonatal exposures to sevoflurane induce neurocognitive dysfunctions in rodents. The lack of cell type–specific information after sevoflurane exposure limits the mechanistic understanding of these effects. In this study, the authors tested the hypothesis that sevoflurane exposures alter the atlas of hippocampal cell clusters and have neuronal and nonneuronal cell type–specific effects in mice of both sexes.
Neonatal mice were exposed to 3% sevoflurane for 2 h at postnatal days 6, 8, and 10 and analyzed for the exposure effects at postnatal day 37. Single-nucleus RNA sequencing was performed in the hippocampus followed by in situ hybridization to validate the results of RNA sequencing. The Morris Water Maze test was performed to test neurocognitive function.
The authors found sex-specific distribution of hippocampal cell types in control mice alongside cell type– and sex-specific effects of sevoflurane exposure on distinct hippocampal cell populations. There were important changes in male but not in female mice after sevoflurane exposure regarding the proportions of cornu ammonis 1 neurons (control vs. sevoflurane, males: 79.9% vs. 32.3%; females: 27.3% vs. 24.3%), dentate gyrus (males: 4.2% vs. 23.4%; females: 36.2% vs. 35.8%), and oligodendrocytes (males: 0.6% vs. 6.9%; females: 5.9% vs. 7.8%). In male but not in female mice, sevoflurane altered the number of significantly enriched ligand–receptor pairs in the cornu ammonis 1, cornu ammonis 3, and dente gyrus trisynaptic circuit (control vs. sevoflurane, cornu ammonis 1–cornu ammonis 3: 18 vs. 42 in males and 15 vs. 21 in females; cornu ammonis 1–dentate gyrus: 21 vs. 35 in males and 12 vs. 20 in females; cornu ammonis 3–dentate gyrus: 25 vs. 45 in males and 17 vs. 20 in females), interfered with dentate gyrus granule cell neurogenesis, hampered microglia differentiation, and decreased cornu ammonis 1 pyramidal cell diversity. Oligodendrocyte differentiation was specifically altered in females with increased expressions of Mbp and Mag. In situ hybridization validated the increased expression of common differentially expressed genes.
This single-nucleus RNA sequencing study reveals the hippocampal atlas of mice, providing a comprehensive resource for the neuronal and nonneuronal cell type– and sex-specific effects of sevoflurane during development.
Multiple neonatal exposures to sevoflurane induce neurocognitive dysfunction in rodents
The cell type–specific mechanisms underlying these cognitive deficits are incompletely understood
Single-nucleus RNA sequencing revealed cell type– and sex-specific effects of repeated sevoflurane exposure in the hippocampus of neonatal mice
These differential effects of sevoflurane on distinct hippocampal cell populations and signaling pathways provide new insights into the mechanisms of actions of anesthetics in the developing brain