🧫
Sevoflurane-induced neurotoxicity (SIN) rat model
active
experiment
Created: 2026-04-06T12:28:17
By: etl-v1-backfill
Quality:
50%
✓ SciDEX
ID: exp-aff90cc4-5f5c-48ea-a980-c024d135d844
🧫 Experiment Protocol
Validationperioperative neurocognitive disordersC1qaratsproposed
This comprehensive study established a rat model of prolonged sevoflurane anesthesia to investigate the mechanisms underlying perioperative neurocognitive disorders. The experiment involved exposing rats to prolonged sevoflurane anesthesia and then conducting extensive behavioral, molecular, and morphological analyses. Behavioral testing included Morris water maze for cognitive function, elevated plus maze and open field test for anxiety-like behaviors. The study employed multiple techniques including transcriptomic analysis (RNA sequencing), electrophysiology, molecular biology assays, scanning electron microscopy, Golgi staining, TUNEL assay, and morphological analysis to characterize the neuropathological changes. The research revealed that prolonged anesthesia triggered NF-κB inflammatory pathway activation, neuroinflammation, reduced neuronal excitability, cognitive dysfunction, and anxiety-like behaviors. RNA sequencing showed downregulation of synaptic genes, while microglial activation, migration, and phagocytosis were enhanced. The study identified complement-mediated microglial synaptic elimination as a key mechanism, with increased C1qa and C3 expression and C1qa tagging of synapses leading to synaptic loss and dendritic spine reduction.
PRIMARY OUTCOME
cognitive dysfunction and anxiety-like behaviors
EXPECTED OUTCOMES
- 1. Primary: Prolonged sevoflurane will increase MWM escape latency by >50% and reduce probe trial time in target quadrant by >30% (p < 0.01)
- 2. Secondary: EPM open arm time will decrease by 40-60% indicating increased anxiety-like behavior
- 3. Tertiary: C1qa, C1qb, C1qc mRNA levels will increase 3-5 fold in sevoflurane groups compared to controls
- 4. Quaternary: Microglial density will increase 2-3 fold with activated morphology (reduced process length and branching)
- 5. Electrophysiological: LTP magnitude will be reduced by 35-50% in sevoflurane-exposed animals
- 6. Morphological: Dendritic spine density will decrease by 25-40% particularly in mushroom spines
- 7. Negative outcome: Short sevoflurane exposure may show intermediate effects (20-30% changes) or no significant differences from controls
SUCCESS CRITERIA
- • Behavioral significance: p < 0.05 with Cohen's d > 0.8 for MWM learning and memory measures
- • Physiological stability: <10% variation in temperature, heart rate during anesthesia with >95% survival rate
- • RNA quality: RIN scores >7.0 for all RNA-seq samples with >20 million mapped reads per sample
- • Histological quality: <5% tissue damage in processed sections with successful immunostaining in >90% of samples
- • Electrophysiological criteria: Stable baseline recordings for ≥20 minutes with LTP lasting ≥60 minutes in controls
- • Reproducibility: Key findings (behavioral deficits, C1qa upregulation) replicated across ≥2 independent cohorts
- • Statistical power: Minimum 80% power achieved for primary behavioral and molecular endpoints
PROTOCOL
**Phase 1: Animal Preparation and Anesthesia Protocol** — Week 1
Use 8-week-old male Sprague-Dawley rats (n=12 per group, Charles River) weighing 250-300g. Randomize into groups: control (room air), short sevoflurane (2h), and prolonged sevoflurane (6h). Fast animals 12h before anesthesia. Induce anesthesia with 8% sevoflurane in 100% O2, maintain at 3-4% with continuous monitoring of heart rate, respiratory rate, SpO2, and rectal temperature (maintain 37±0.5°C). Monitor blood glucose and arterial blood gases every 2h. Control group receives identical handling without anesthesia. Include positive control group with LPS injection (1 mg/kg IP, Sigma L2630) 24h before sacrifice.
**Phase 2: Behavioral Testing Battery** — Week 2-3
Begin behavioral testing 24h post-anesthesia. Conduct Morris Water Maze (MWM) over 5 days: 4 trials/day for spatial learning (days 1-4), probe trial on day 5. Record escape latency, swim speed, path length, and time in target quadrant using EthoVision XT software. Perform elevated plus maze (EPM) on day 6: 5-minute test measuring time in open/closed arms, entries, and anxiety index. Conduct open field test on day 7: 10-minute session recording total distance, center time, rearing frequency, and grooming episodes. Include 1-week washout period, then repeat behavioral battery to assess persistence of deficits.
**Phase 3: Electrophysiological Analysis** — Week 3-4
Prepare acute hippocampal slices (400 μm) 48h post-anesthesia using standard ACSF (124 mM NaCl, 3 mM KCl, 1.25 mM NaH2PO4, 26 mM NaHCO3, 2 mM CaCl2, 1 mM MgSO4, 10 mM glucose). Record field excitatory postsynaptic potentials (fEPSPs) from CA1 stratum radiatum using glass microelectrodes (2-4 MΩ). Stimulate Schaffer collaterals with increasing intensities (10-100 μA) to generate input-output curves. Induce long-term potentiation (LTP) with high-frequency stimulation (100 Hz, 1 sec, repeated 4x at 20-sec intervals). Record baseline for 20 min, then monitor fEPSP slope for 60 min post-tetanization. Measure paired-pulse facilitation at 50, 100, 200, 500 ms intervals.
**Phase 4: Molecular and Histological Analysis** — Week 4-5
Sacrifice animals 48h post-anesthesia for tissue collection. Rapidly extract hippocampus and cortex, divide sagittally: one half flash-frozen for RNA/protein analysis, other half fixed in 4% PFA for histology. Perform RNA-seq on hippocampal tissue (n=6 per group) using Illumina HiSeq platform after quality control (RIN >7). Analyze differential gene expression focusing on complement pathway genes (C1qa, C1qb, C1qc, C3, C4a), inflammatory markers (TNF-α, IL-1β, IL-6), and synaptic proteins (PSD95, synaptophysin, SNAP25). Validate key genes by qRT-PCR using custom TaqMan arrays.
**Phase 5: Immunohistochemistry and Morphological Assessment** — Week 5-6
Process fixed tissue for immunohistochemistry using standard protocols. Primary antibodies: Iba1 (Wako 019-19741, 1:1000) for microglia, C1qA (Abcam ab182451, 1:500), NF-κB p65 (Cell Signaling 8242, 1:800), MAP2 (Millipore AB5622, 1:1000) for dendrites, and synaptophysin (Sigma S5768, 1:2000). Use fluorescent secondary antibodies and DAPI counterstain. Acquire images on confocal microscope (Olympus FV3000) with identical settings. Quantify microglial density, morphology (process length, branch points), C1qA puncta density, and synaptic protein colocalization using ImageJ plugins (Skeleton Analysis, Colocalization Threshold).
**Phase 6: Advanced Morphological Techniques** — Week 6-7
Perform Golgi-Cox staining (FD NeuroTechnologies kit PK401) on separate tissue sections following manufacturer's protocol. Image pyramidal neurons in CA1 and cortical layer 2/3 using 100x oil immersion objective. Analyze dendritic spine density and morphology (thin, stubby, mushroom) on secondary dendrites using Neurolucida software. Conduct TUNEL assay (Roche 11684817910) to quantify apoptotic cells in hippocampus and cortex. Process samples for scanning electron microscopy: fix in 2.5% glutaraldehyde, post-fix with 1% osmium tetroxide, dehydrate through graded ethanols, and coat with gold-palladium for imaging synaptic ultrastructure.
LINKED HYPOTHESES
Source: PMID 36600274 ↗
🧫 Experiment Extras
PATHWAY
complement cascade, NF-κB inflammatory pathway
MARKET PRICE
$0.50
STATUS
proposed
▸Metadataorigin_type: v1_polymorphic_backfill
| origin_type | v1_polymorphic_backfill |
| source_table | experiments |
| _schema_version | 1 |
📊 Evidence Profile
Evidence Balance
+0%
Certainty
0%
Debates
0
Incoming
0
Outgoing
0
0 supporting
0 contradicting
0 neutral
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