Melatonin Regulates Microglia-derived Exosomes to Reduce Postoperative Delirium

At the animal level, a rat model of postoperative delirium was constructed by deep anesthesia and treated intraperitoneally and respectively with low, medium, and high doses of melatonin. The behavior changes of rats were detected by open field test and food burial test after 6 h and 24 h of administration. HE staining was used to observe the pathological changes of each hippocampus. Tunel staining was used to detect apoptosis, ferroptosis detection kit was used to detect differences in iron ion levels. WB and qPCR were used to detect the expression of GPX4, SLC7A11, ACSL4, TFR1, ZO-1, TNF-a, IL-4, and IL-6, and immunofluorescence was used to detect the expression levels of Iba-1/CD86 and Iba-1/CD206. At the cellular level, immortalized murine microglia cells (BV2) were treated with LPS to induce an inflammatory state and treated with low, medium, and high doses of melatonin. apoptosis in each group was detected by flow cytometry 24 h later, and ELISA was used to detect the contents of TNF-a, IL-1β, IL-6, iNOS, and Arg-1 in the cell supernatants of each group. The levels of CD86 and CD206 in each group were detected by flow cytometry; the exosomes from control microglia BV2 (blank control group), LPS-treated microglia (model group) and melatonin treated model group were identified and were co-cultured with rat hippocampal neurons HT22. The apoptosis of neurons was detected by flow cytometry 24 hours later, and iron ion levels in neurons were detected by iron ion detection kit. WB was used to detect the protein expression of GPX4, SLC7A11, ACSL4, and TFR1.Transmission electron microscopy was used to detect neurons microstructure.