Ginkgolide B Suppresses Methamphetamine-Induced Microglial Activation Through TLR4-NF-κB Signaling Pathway in BV2 Cells.

Accumulating evidence suggests that microglial cells have altered morphology and proliferation in different brain regions of methamphetamine (Meth) abusers and Meth-abusing animal models. However, the possible mechanisms underlying Meth-induced microglial activation remain poorly understood. Meanwhile, Toll-like receptor4 (TLR4) is closely associated with inflammation. Therefore the aim of the present study was to assess whether Meth treatment affects TLR4 expression; in addition, we evaluated the effects of ginkgolide B (GB), a diterpene lactone extracted from Ginkgo biloba, on Meth-mediated inflammation. BV2 cells were treated with Meth. Interestingly, Meth treatment significantly increased TLR4 expression, activated the NF-κB signaling pathway, and promoted TNF-α, IL-6 and IL-1β excretion. These effects, however, were partially attenuated by GB pre-treatment. To further confirm the role of TLR4 in Meth-mediated inflammation, the siRNA technology was applied to knock down TLR4, which resulted in hampered Meth-mediated inflammatory responses, confirming the important role of TLR4 in this process. Taken together, our findings suggested that Meth exposure results in BV2 cell activation, in association with TLR4 upregulation. GB could attenuate Meth-induced inflammation, at least partially through TLR4-NF-κB signaling pathway, therefore, targeting TLR4 may constitute a potential intervention strategy for Meth mediated neuroinflammation.