黄芩苷通过抑制小胶质细胞活化缓解吗啡耐受

Baicalin attenuates morphine tolerance through suppressing spinal microglia activation in mice

探讨黄芩苷对小胶质细胞活化和慢性耐受的影响并考察其作用机制。应用RT-PCR和ELISA法考察细胞释放炎症因子IL-1β和TNF-α的变化,Western blot法检测细胞中p-p38MAPK和IBA-1蛋白表达变化,热板法检测慢性吗啡耐受小鼠热板痛阈变化。实验结果发现,黄芩苷(1,10,100μmol/L)剂量依赖性地抑制吗啡活化的BV2细胞释放IL-1β和TNF-α,100μmol/L黄芩苷明显降低p-p38MAPK水平。鞘内注射黄芩苷(20,40,60μg)可剂量依赖性地改善慢性吗啡耐受,鞘内注射黄芩苷60μg可模拟出小胶质细胞抑制剂米诺环素的作用并能显著抑制慢性吗啡耐受小鼠脊髓p-p38MAPK以及IBA-1的表达。本研究表明,黄芩苷可通过抑制p38MAPK信号通路抑制吗啡引起的小胶质细胞活化,进而显著改善慢性吗啡耐受。

The aim of the present study was to investigate the effects and possible mechanisms of baicalin on morphine induced microglia activation and morphine tolerance. Cytokine IL-1β and TNF-α expression were analyzed by reverse transcription polymerase chain reaction （RT-PCR） and enzyme-linked immunosorbent assay （ELISA）, and the level of p38 MAP kinase phosphorylation and IBA-1 expression was determined by Western blot, the antinociception and morphine tolerance were assessed in mice using hot-plate test. Results showed that baicalin （ 1, 10,100 μmol/L） inhibited morphine induced up-regulated levels of IL-1β, TNF-α in BV-2 microglia cells in a dose-dependent manner; and that 100 μmol/L baicalin significantly inhibited the level of p38MAP kinase phosphorylation induced by morphine in BV2 microglia cells. Intrathecal （ it. ） injection of baicalin （20, 40, 60 μg） attenuated the development of chronic morphine tolerance in a dose-dependent manner. Baicalin （60 μg） mimicked the role of minocycline and significantly suppressed the level of p38MAP kinase phosphorylation induced bychronic morphine treatment and IBA-1 expression in mice spinal cord. In conclusion, baicalin suppresses morphine-induced microglia activation through suppressing p38MAPK signaling, resulting in significant attenuation of morphine antinociceptive tolerance.