AM1241 preconditioning reduces microglial activation and injury induced by lipopolysaccharide

Objective To investigate the effect of preconditioning with cannabinoid CB2 receptor agonist AM1241 on microglial activation and injury induced by lipopolysaccharide ( LPS) and interferon-γ (IFN-γ). Methods The microglial cells were chosen and assigned to control group,AM1241 treatment group, LPS/IFN-γ inducement group and AM1241+LPS/IFN-γ treatment group. Cells of control group were cultured in normal medium;cells of AM1241 treatment group were preconditioned with AM 1241 for 2 h, and then the medium was changed with normal medium;cells of LPS/IFN-γ inducement group were exposed to the medium containing 1 μg/mL LPS plus 50 U/mL IFN-γ for 24 h;cells of AM1241+LPS/IFN-γ treatment group were preconditioned with AM1241, then the medium were changed with normal medium for 2 h, and at last, cells of this group were exposed to 1 μg/mL LPS plus 50 U/mL IFN-γ for 24 h. Microglial metabolism was assessed by MTT assay;NO release was measured by Reagent Kit;microglial shapes were observed through microscope. Results CB2 receptor agonist preconditioning can up-regulate the microglial CB2 receptor expression markedly;cell metabolism of AM1241+LPS/IFN-γ treatment group (92.55 ±8.37%) was obviously higher than that of LPS/IFN-γ inducement group (75.04±3.01%, P<0.05);AM1241+LPS/IFN-γ treatment group (43.44±5.52 μmol/L) released significantly less NO than LPS/IFN-γ inducement group (90.87±4.28 (μmol/L, P<0.05). Cells of the LPS/IFN-γ inducement group were destroyed seriously with enlarged soma and thickened and shortened pseudopodium;cells of the AM1241+LPS/IFN-γ treatment group were destroyed slightly with slightly enlarged soma and thickened and shortened pseudopodium. Conclusion Preconditioning with cannabinoid CB2 receptor agonist AM1241 reduces microglial activation and injury induced by LPS plus IFN-γ. Key words: Microglia; Activation; Injury; Preconditioning