Hippocampal estrogens rescued the decline of synaptic plasticity after surgery and anesthesia by inhibiting microglia overactivation.
Level 5 - mechanism / opinion, no new human data
Animal model experiment without human participants
PubMed 38056710 · doi:10.1016/j.bbr.2023.114794
What was done
Researchers evaluated the neuroprotective role of hippocampal estrogens against postoperative cognitive dysfunction (POCD) in 15-month-old male and female C57BL/6 J mice subjected to exploratory laparotomy under anesthesia. Animals were treated with estrogens, estrogen receptor inhibitors, or combinations. Memory capacity was evaluated using hippocampal-dependent behavioral tests. Hippocampal estrogen concentrations were quantified by ELISA, while microglial activation and synaptic plasticity-related protein expression were measured via Western blot and immunofluorescence.
What was found
Female mice did not develop POCD following surgery and anesthesia (P > 0.05), but administering an estrogen receptor inhibitor significantly impaired their cognitive function (P < 0.05). Conversely, male mice developed significant cognitive impairment post-surgery, which was rescued by estrogen supplementation (P < 0.05); this rescue was abolished when co-administered with an estrogen receptor inhibitor (P < 0.05). Hippocampal estrogen levels correlated negatively with microglial activation (P < 0.05). Specific numerical values for behavioral scores, protein levels, and sample sizes per group were not reported in the abstract.
Why it matters
The study suggests a mechanistic explanation for sex differences observed in postoperative cognitive impairment, showing that estrogen signaling suppresses microglial overactivation and preserves synaptic plasticity in aging rodent brains.
Limits
The abstract provides no exact animal counts, specific dosages, or numerical effect sizes, providing only p-value thresholds. Findings are restricted to a rodent model of laparotomy and cannot be directly extrapolated to human clinical surgical outcomes without clinical validation.
Cited by
- supports Estrogen acts as an immunomodulator and directly modulates neuroplasticity.