エピガロカテキン-3-ガレートのミクログリア分化調節による高齢ラットにおける術後認知機能障害の予防効果：動物実験的研究

This study evaluated the effect of epigallocatechin-3-gallate (EGCG), a flavonoid, on postoperative cognitive dysfunction by modulating microglial phenotype expression in aged rats following general anesthesia with isoflurane. Eighteen-month-old male Sprague-Dawley rats were randomly assigned to the EGCG and control groups. EGCG in distilled water (DW) or DW alone was administered orally for 7 days before anesthesia. After anesthesia, cognitive function was assessed using the Y-maze test, and neuronal damage was evaluated histologically. Microglial activation and phenotype differentiation were also analyzed. At 24 h after anesthesia, the alternation ratio was significantly higher in the EGCG group than in the control group (70.00 ± 7.98% vs. 28.14 ± 11.52%, p < 0.001). The EGCG group exhibited reduced neuronal damage and microglial activation. Additionally, M1 phenotype activation was significantly lower (30.03 ± 7.73% vs. 51.00 ± 9.83%, p < 0.001), and M2 phenotype activation was significantly higher (17.61 ± 5.52% vs. 5.99 ± 2.46%, p < 0.001) in the EGCG group than in the control group. In summary, pre-anesthetic administration of EGCG modulated microglial phenotype differentiation, reduced neuronal damage, and improved postoperative cognitive function in aged rats following general anesthesia.