A Study On Curcumin Inhibits COX-2 Expression In Activated Microglia

Object: To investigate the role of cyclooxygenase 2 (COX-2) in the production of cytokines by microglia in response to the stimulation of lipoplysaccharide (LPS) and its possible mechanism. To identify curcumin's neuroprotective effects based on supressing COX-2 expression.Method: The cytotoxicity of curcumin and LPS was measured by WST-1. The effect of inflammation on COX-2 expression and c-Jun N-terminal kinase (JNK) phosphorylation in the microglia was determined by Western blotting. Furthermore, we use the specific inhibitor of JNK: SP600125 and curcumin to inhibit the phosphorylation of JNK, and then tested the expression of COX-2. Finally, we tested the neurotoxicity of supernatant of microglia which stimulated by LPS upon curcumin pretreatment.Result: 1. Upon stimulation, we find the upregulation of COX-2 expression and JNK activation in the BV-2 cells. 2.JNK inhibitor SP600125 and curcumin partly inhibit COX-2 expression induced by LPS in the BV-2 cells. 3.Furthermore, a significant reduction of neurotoxicity had been found in the curcumin pretreatment group compared with the control group.Conclusion: This study is the first report demonstrated that curcumin could protect neuron from neuroinflammation, which involved the JNK-mediated COX-2 induction in microglia upon the stimulation of LPS.