Background

Postoperative cognitive dysfunction (POCD) is a central nervous system (CNS) complication and occurs quite frequently after anesthesia, especially in elderly patients. DNA (cytosine-5)-methyltransferase 3-like (DNMT3L) is an enzymatically inactive regulatory factor that can modulate gene expression via methylation. Few studies specifically focused on the role of DNMT3L in sevoflurane-induced POCD.

Objective

The cognitive dysfunction was determined by Morris water maze assay. Hippocampal neuron apoptosis was measured by TdT-mediated dUTP nick-end labeling (TUNEL) assay. Neuron proliferation and apoptosis were measured by cell counting kit-8 (CCK-8) and flow cytometry assay. The expression levels of DNMT3L and postsynaptic density protein-95 (PSD95) were measured by qRT-PCR and western blot.

Results

The sevoflurane-induced POCD aging rat model was established for in vivo study. Suppression of DNA methylation by 5-Aza-2′-deoxycytidine (5-AZA; a widely used methylation inhibitor) reversed sevoflurane-induced cognitive dysfunction and hippocampal neuron apoptosis in rats. Moreover, sevoflurane enhanced DNMT3L expression and induced methylation of PSD95 promoter in vivo. In vitro, sevoflurane induced neuronal apoptosis and DNMT3L expression to promote PSD95 methylation. Finally, rescue experiments indicated that sevoflurane induced neuron apoptosis by increasing DNMT3L expression and promoting methylation of PDS95 in POCD.

Conclusion

Sevoflurane induced neuronal apoptosis by increasing DNMT3L expression and promoting methylation of PDS95 in vivo and in vitro, providing a novel therapeutic strategy for POCD.

中文翻译：

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七氟醚在术后认知功能障碍中通过增强DNMT3L表达和促进PSD95启动子甲基化来诱导神经元凋亡

背景

术后认知功能障碍（POCD）是中枢神经系统（CNS）并发症，在麻醉后尤其是老年患者中非常常见。DNA（cytosine-5）-methyltransferase 3-like（DNMT3L）是一种无酶活性的调节因子，可通过甲基化调节基因表达。很少有研究专门研究DNMT3L在七氟醚诱导的POCD中的作用。

客观的

认知功能障碍是通过莫里斯水迷宫实验确定的。通过TdT介导的dUTP缺口末端标记（TUNEL）测定法检测海马神经元的凋亡。通过细胞计数试剂盒8（CCK-8）和流式细胞仪检测神经元的增殖和凋亡。用qRT-PCR和western blot检测DNMT3L和突触后密度蛋白95（PSD95）的表达水平。

结果

建立了七氟醚诱导的POCD衰老大鼠模型用于体内研究。5-Aza-2'-脱氧胞苷（5-AZA；一种广泛使用的甲基化抑制剂）抑制DNA甲基化可逆转七氟醚诱导的大鼠认知功能障碍和海马神经元凋亡。此外，七氟醚在体内增强了DNMT3L的表达并诱导了PSD95启动子的甲基化。在体外，七氟醚诱​​导神经元凋亡和DNMT3L表达，以促进PSD95甲基化。最后，救援实验表明七氟醚通过增加DNMT3L的表达并促进POCD中PDS95的甲基化来诱导神经元凋亡。

结论

七氟醚通过增加DNMT3L的表达并促进体内和体外PDS95的甲基化来诱导神经元凋亡，为POCD提供了新的治疗策略。