Genotype-dependent reconfiguration of hippocampal transcriptional responses to anesthesia/surgery at 24 h in 5xFAD mice: an exploratory interaction-based analysis

Abstract Background Perioperative neurocognitive disorders (PND) are recognized complications after anesthesia and surgery. Alzheimer-related brain states may increase vulnerability, but whether this susceptibility reflects a quantitatively larger or qualitatively distinct acute molecular response remains unclear. We addressed this question using a 5xFAD mouse cohort as an exploratory model of an amyloid-associated brain state. Methods Hippocampal bulk RNA sequencing was performed in 4-month-old female wild-type (WT) and 5xFAD mice 24 h after control handling or combined isoflurane anesthesia and abdominal surgery ( n = 3 per factorial cell). DESeq2 was used to estimate genotype, exposure, and genotype-by-exposure effects. Additional sensitivity analyses included effect-size filtering, 12 leave-one-sample-out fits, edgeR quasi-likelihood modeling, and Cook’s-distance diagnostics. Mouse Hallmark gene-set enrichment analysis (GSEA), four marker-based cell-type-associated expression scores, and two public mouse transcriptomic datasets were used for pathway and external context. Results WT and 5xFAD within-genotype contrasts identified 20 and 3 exposure-associated genes, respectively, at false discovery rate (FDR) < 0.05. The DESeq2 interaction identified 53 genes at FDR < 0.05; 37 also had |interaction log2FC| ≥ 1. All 53 had opposite-signed exposure-effect estimates in WT and 5xFAD mice, although separate within-genotype significance was not required. All retained their direction in 12 leave-one-out fits and in edgeR, and none exceeded the Cook’s-distance cutoff. However, no gene reached genome-wide FDR < 0.05 in edgeR, indicating method-dependent gene-level significance. Interaction-ranked GSEA identified 10 Hallmark pathways at FDR < 0.05, including positive interaction enrichment of TNF-alpha/NF-kappaB and interferon programs and negative interaction enrichment of oxidative phosphorylation and lipid/metabolic programs. All 10 retained direction and FDR < 0.05 in edgeR-ranked GSEA. None of the four marker-based scores had a significant interaction. No highlighted gene replicated at FDR < 0.05 in the external datasets. Conclusions In this small exploratory cohort, the 5xFAD genotype was associated with a directionally reorganized 24-h hippocampal transcriptional response to combined anesthesia and surgery. Pathway-level immune-metabolic interaction patterns were more robust than individual-gene significance. The findings do not establish a perioperative neurocognitive disorder phenotype, distinguish anesthesia from surgical effects, or validate biomarkers; they provide hypotheses for larger, longitudinal, behaviorally phenotyped, and experimentally validated studies.