Department of NeurologyI, Clinical Medical College of DaLi University, No.32, Jiashibo Avenue, Dali Bai Autonomous Prefecture, 671000, Yunnan, China.
Inflammation. 2021 Oct;44(5):1750-1761. doi: 10.1007/s10753-021-01451-w. Epub 2021 Apr 19.
The blood-brain barrier (BBB) is important for protecting the brain tissue by selectively exchanging substances between the blood and brain. The integrity of the BBB can be damaged by multiple factors, including oxidative stress and inflammation. Ramelteon is an oral hypnotic drug, and in the present study, we investigated its protective effect on BBB damage, as well as the underlying mechanism. LPS was used to induce BBB damage on mice and stimulate injury on endothelial cells. Evans blue staining assay was used to measure the brain permeability. The expressions of ZO-1 and Occludin were evaluated using immunostaining and Western blot in the brain tissue and endothelial cells, respectively. qRT-PCR and ELISA were used to detect the production of IL-1β and MCP-1 in the brain vessels. TBA assay was utilized to examine the concentration of MDA in the brain tissue and endothelial cells. The expression of Nrf2 in the nucleus and NQO1 were determined using Western blot assay. The endothelial permeability of the monolayer was examined using the FITC-dextran permeation assay. Firstly, the increased brain permeability and downregulated expression of tight junction proteins in the brain tissue induced by LPS were significantly reversed by treatment with Ramelteon, accompanied by the decrease in the production of IL-1β and MCP-1 in the vessels in mice. Also, the Nrf2 signaling was activated and oxidative stress in the brain vessels was alleviated by treatment with Ramelteon. Secondly, LPS-induced increase in endothelial monolayer permeability and decrease in tight junction protein expression in bEnd.3 brain endothelial cells were significantly reversed by Ramelteon, accompanied by activated Nrf2 signaling and alleviated oxidative stress. Lastly, the protective effects of Ramelteon against LPS-induced reduction of ZO-1 and Occludin, and the increase in endothelial monolayer permeability were dramatically abolished by silencing Nrf2. Ramelteon might ameliorate LPS-induced hyperpermeability of the BBB by activating the Nrf2 signaling pathway.
血脑屏障（BBB）通过在血液和大脑之间选择性地交换物质来保护脑组织，其完整性可被多种因素破坏，包括氧化应激和炎症。雷美替胺是一种口服催眠药物，在本研究中，我们研究了它对 BBB 损伤的保护作用及其潜在机制。LPS 用于诱导小鼠 BBB 损伤并刺激内皮细胞损伤。伊文思蓝染色法用于测量脑通透性。免疫染色和 Western blot 分别用于评估脑组织和内皮细胞中 ZO-1 和 Occludin 的表达。qRT-PCR 和 ELISA 用于检测脑血管中 IL-1β和 MCP-1 的产生。TBA 法用于检测脑组织和内皮细胞中 MDA 的浓度。Western blot 法用于检测核中 Nrf2 和 NQO1 的表达。FITC-葡聚糖渗透试验用于检测单层内皮通透性。首先，LPS 诱导的脑通透性增加和紧密连接蛋白表达下调在雷美替胺治疗后显著逆转，同时小鼠血管中 IL-1β和 MCP-1 的产生减少。此外，雷美替胺激活了 Nrf2 信号通路并减轻了脑血管的氧化应激。其次，LPS 诱导的 bEnd.3 脑内皮细胞单层通透性增加和紧密连接蛋白表达下调在雷美替胺治疗后显著逆转，同时激活了 Nrf2 信号通路并减轻了氧化应激。最后，沉默 Nrf2 显著消除了雷美替胺对 LPS 诱导的 ZO-1 和 Occludin 减少以及内皮单层通透性增加的保护作用。雷美替胺可能通过激活 Nrf2 信号通路改善 LPS 诱导的 BBB 高通透性。
