Effect of Tetramethylpyrazine on Pro-Inflammatory Cytokine Expressions in Mouse Brain Tissue following Intracerebroventricular Lipopolysaccharide Treatment

Objectives : Tetramethylpyrazine (TMP) is an active ingredient in Ligusticum wallichii and has a wide range of neuroprotection effects. This study investigated anti-neuroinflammatory effect of TMP on brain regions in intracerebroventricular (i.c.v.) lipopolysaccharide (LPS)-treated C57BL/6 mice. Methods : TMP was administered intraperitoneally at doses of 10, 20, and 30 mg/kg at 1 h prior to LPS (3 mg/kg) i.c.v. injection. mRNA level of pro-inflammatory cytokines, including tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), interleukin (IL)-$1{\beta}$ and IL-6, was measured in the cerebral cortex, hippocampus, and hypothalamus tissue using real-time polymerase chain reaction at 24 h after the LPS injection. Cyclooxygenase-2 (COX-2) positive cells in the hypothalamus was also observed using immunohistochemistry at 24 h after the LPS injection. Results : At a dose of 30 mg/kg TMP significantly attenuated up-regulation of TNF-${\alpha}$ and IL-$1{\beta}$ mRNA in the cerebral cortex and IL-$1{\beta}$ mRNA in the hippocampus. In the hypothalamus, doses of 20 mg/kg and 30 mg/kg TMP significantly attenuated up-regulation of TNF-${\alpha}$, IL-$1{\beta}$, and IL-6 mRNA induced by the LPS injection. In addition, TMP (30 mg/kg) significantly reduced the number of COX-2 positive cells in the hypothalamus. Conclusion : These results indicate that TMP has an anti-inflammatory effect on neuroinflammation, especially in the hypothalamus, induced by LPS i.c.v. injection and suggest that TMP-containing Ligusticum wallichii may play a modulatory role on the systemic responses following hypothalamic inflammation.

Tetramethylpyrazine이 LPS의 뇌실주입에 따른 생쥐 뇌조직의 Pro-Inflammatory Cytokines 발현에 미치는 영향