TLR4受体拮抗剂对Aβ1-42诱导的小胶质细胞炎性因子分泌的影响

Effect of TLR4 antagonist on the secretion of inflammatory cytokines in microglia induced by Aβ1-42

目的探讨体外培养条件下Toll样受体4(TLR4)拮抗剂对β淀粉样蛋白1-42片段(Aβ1-42)诱导的小胶质细胞炎性因子分泌的影响。方法用不同浓度的Aβ1-42(终浓度为0、1、5、10、20、40、80μmol/L)及TAK-242(终浓度1μmol/L)处理小鼠小胶质细胞(BV2),24 h后取其上清干预小鼠海马神经元(HT22)。48 h后,应用CCK8方法检测HT22细胞的存活,ELISA方法检测BV2细胞上清液中TNF-α、IL-1β水平。结果与空白对照组相比,Aβ1-42直接作用于体外培养的小胶质细胞后,以剂量依赖的方式诱导TNF-α、IL-1分泌的增加(P<0.05);与空白对照组相比,Aβ1-42诱导组培养液干预的HT22细胞存活率显著下降(P<0.05)。给予TLR4拮抗剂TAK-242干预后,Aβ1-42诱导TNF-α、IL-1分泌的作用被抑制,细胞分泌TNF-α、IL-1β水平较Aβ1-42诱导组显著降低(P<0.05),HT22细胞存活率也显著提高(P<0.05)。结论阻断TLR4可抑制Aβ1-42诱导的小胶质细胞炎性因子的分泌,并减轻活化的小胶质细胞对海马神经元的损害。

Objective To investigate the effect of Toll-like receptor 4（ TLR4） antagonist on the secretion of inflammatory cytokines in microglia induced by Amyloid β protein 1-42（ Aβ1-42）.Methods Cultured microglia cells（ BV2） were stimulated with different concentrations of Aβ1-42（ final concentrations of 0,1,5,10,20,40 and 80 μmol/L） and TLR4 antagonist（ TAK-242,1 μmol / L） for 24 h,respectively. The supernatants were used to treat cultured hippocampus neurons（ HT22） for 48 h. The viability of HT22 cells was tested by CCK8 kit,and levels of tumor necrosis factor-α（ TNF-α） and interleukin l-β（ IL-1β） in the culture medium were detected by method of ELISA. Results Compared with control group,treatment of Aβ1-42 significantly increased the levels of TNF-α and IL-1β in cultured microglia cells in a dose-dependent manner（ P 〈 0. 05）. In addition,Aβ1-42 treated supernatants induced a significant decrease of viability in cultured HT22 cells compared with non supernatant treated control（ P 〈 0. 05）. Compared with non-TAK-242 treated group,TAK-2 4 2 significantly inhibited the increase of TNF-α and IL-1 β in cultured microglia cells（ P 〈 0. 05）,and attenuated the neuronal death induced by the supernatants from cultured microglia treated by Aβ1-42（ P 〈 0. 05）. Conclusion Blocking TLR4 by antagonist can inhibit the release of cytokines from microglia induced by Aβ1-42,and attenuate the damage of neurons induced by supernatants from cultured microglia treated with Aβ1-42.