Z-ligustilide attenuates lipopolysaccharide-induced proinflammatory response via inhibiting NF-κB pathway in primary rat microglia
Abstract
Aim: To investigate the anti-inflammatory effect of Z-ligustilide (LIG) on lipopolysaccharide (LPS)-activated primary rat microglia.
Methods: Microglia were pretreated with LIG 1 h prior to stimulation with LPS (1 μg/mL). After 24 h, cell viability was tested with MTT, nitric oxide (NO) production was assayed with Griess reagent, and the content of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and monocyte chemoattractant protein (MCP-1) was measured with ELISA. Protein expression of the nuclear factor-κB (NF-κB) p65 subunit, cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS) was detected with immunocytochemistry 1 h or 24 h after LPS treatment.
Results: LIG showed a concentration-dependent anti-inflammatory effect in LPS-activated microglia, without causing cytotoxicity. Pretreatment with LIG at 2.5, 5, 10, and 20 μmol/L decreased LPS-induced NO production to 75.9%, 54.4%, 43.1%, and 47.6% (P<0.05 or P< 0.01), TNF-α content to 86.2%, 68.3%, 40.1%, and 39.9% (P<0.01, with the exception of 86.2% for 2.5 μmol/L LIG), IL-1β content to 31.5%, 27.7%, 0.6%, and 0% (P<0.01), and MCP-1 content to 84.4%, 50.3%, 45.1%, and 42.2% (P<0.05 or P<0.01), respectively, compared with LPS treatment alone. LIG (10 μmol/L) significantly inhibited LPS-stimulated immunoreactivity of activated NF-κB, COX-2, and iNOS (P<0.01 vs LPS group).
Conclusion: LIG exerted a potent anti-inflammatory effect on microglia through inhibition of NF-κB pathway. The data provide direct evidence of the neuroprotective effects of LIG and the potential application of LIG for the treatment of the neuroinflammatory diseases characterized by excessive microglial activation.
Keywords:
Methods: Microglia were pretreated with LIG 1 h prior to stimulation with LPS (1 μg/mL). After 24 h, cell viability was tested with MTT, nitric oxide (NO) production was assayed with Griess reagent, and the content of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and monocyte chemoattractant protein (MCP-1) was measured with ELISA. Protein expression of the nuclear factor-κB (NF-κB) p65 subunit, cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS) was detected with immunocytochemistry 1 h or 24 h after LPS treatment.
Results: LIG showed a concentration-dependent anti-inflammatory effect in LPS-activated microglia, without causing cytotoxicity. Pretreatment with LIG at 2.5, 5, 10, and 20 μmol/L decreased LPS-induced NO production to 75.9%, 54.4%, 43.1%, and 47.6% (P<0.05 or P< 0.01), TNF-α content to 86.2%, 68.3%, 40.1%, and 39.9% (P<0.01, with the exception of 86.2% for 2.5 μmol/L LIG), IL-1β content to 31.5%, 27.7%, 0.6%, and 0% (P<0.01), and MCP-1 content to 84.4%, 50.3%, 45.1%, and 42.2% (P<0.05 or P<0.01), respectively, compared with LPS treatment alone. LIG (10 μmol/L) significantly inhibited LPS-stimulated immunoreactivity of activated NF-κB, COX-2, and iNOS (P<0.01 vs LPS group).
Conclusion: LIG exerted a potent anti-inflammatory effect on microglia through inhibition of NF-κB pathway. The data provide direct evidence of the neuroprotective effects of LIG and the potential application of LIG for the treatment of the neuroinflammatory diseases characterized by excessive microglial activation.