Actin Reorganization in Hippocampal Neurons May Play Roles in Early Impairment of Learning and Memory in Rats After Propofol Anesthesia

Abstract

Background Perioperative neurocognitive disorder (PND) is a kind of neuronal complication especially observed in elderly patients. The present study was conducted to observe the changes of actin in hippocampus after propofol anesthesia, and to evaluate their roles in consequent learning impairment in both young (3-month-old) and aged (20-month-old) male rats.Methods Double-shuttle box was used to learning evaluation since1, 3, 7 or 14d after anesthesia. Hippocampi were removed after evaluations. F-actin content and the spines were observed through immunofluorescence and laser scanning confocal microscope (LSCM).Results In young rats, latency of escape response (LER) was prolonged within 3 days after anesthesia. However, LER was significantly prolonged until 7days after anesthesia in elderly rats. Moreover, the learning curves were also shift in old rats. Dendritic spines became smaller in anesthesia groups of aged rats within 3 days, where the F-actin contents were significantly increased until 14d post anesthesia.Conclusion Our results indicate that learning ability could be inhibited until after propofol anesthesia especially in old rats. The over-polymerization of actin and the consequent reorganization of dendrite spines in hippocampus may be responsible, which provides fresh evidence in aspect of synaptic plasticity for PND mechanism.

Membrane nanodomains homeostasis during propofol anesthesia as function of dosage and temperature

“…(Platholi et al, 2014) A new preprint reports that propofol anesthesia in rats leads to week-long perturbation of actin structure and learning. (Zhang, Li and Wu, 2020) Those studies have suggested that the anesthetics act directly on actin, but found no evidence for a mechanism. Instead, our results suggest that the anesthetics primarily act in the lipid bilayer part of the membrane by destabilizing lipid nanodomains.…”