Mechanism by which nobiletin inhibits inflammatory response of BV2 microglia

Chi Wenxin; Zhang Cunxin; Gao Kai; Lyu Chaoliang; Zhang Kefeng

doi:10.12307/2024.741

Abstract：BACKGROUND:Nobiletin has been found to improve lipopolysaccharide-induced abnormal activation of microglia,excessive release of inflammatory factors and redox imbalance.However,the specific mechanism is not fully understood. OBJECTIVE:To investigate the molecular mechanism by which nobiletin can inhibit lipopolysaccharide-induced inflammation in BV2 microglia. METHODS:Passage 3 BV2 microglia were divided into three groups:control group was cultured for 24 hours(without any treatment).Lipopolysaccharide group was treated with 10 μg/mL lipopolysaccharide for 24 hours.Lipopolysaccharide+nobiletin group was treated with 20 μmol/L nobiletin for 6 hours and then 10 μg/mL lipopolysaccharide for 24 hours.After the processing,cell proliferation was detected by CCK-8 assay.The level of intracellular reactive oxygen species was detected by fluorescent probe.The mRNA expression levels of nuclear factor κB p65,tumor necrosis factor α,and interleukin-1β were detected by qRT-PCR.The protein expression levels of nuclear factor κB p65,p-nuclear factor κB p65,tumor necrosis factor α,and interleukin-1β were detected by western blot assay. RESULTS AND CONCLUSION:(1)Compared with the control group,the proliferation activity of lipopolysaccharide group was decreased(P<0.001).Compared with the lipopolysaccharide group,the cell proliferation activity of lipopolysaccharide+nobiletin group was increased(P<0.001).(2)Compared with the control group,the level of intracellular reactive oxygen species was increased in the lipopolysaccharide group(P<0.001).Compared with the lipopolysaccharide group,the level of intracellular reactive oxygen species was decreased in the lipopolysaccharide+nobiletin group(P<0.01).(3)Compared with the control group,the mRNA expression levels of tumor necrosis factor α and interleukin-1β were increased in the lipopolysaccharide group(P<0.001,P<0.01).Compared with the lipopolysaccharide group,mRNA expression levels of tumor necrosis factor α and interleukin-1β were decreased in the lipopolysaccharide+nobiletin group(P<0.01,P<0.05).(4)Compared with the control group,the protein expression levels of p-nuclear factor κB p65,tumor necrosis factor α,and interleukin-1β in were increased the lipopolysaccharide group(P<0.001).Compared with the lipopolysaccharide group,the expression of p-nuclear factor κB p65,tumor necrosis factor α,and interleukin-1β was decreased in the lipopolysaccharide+nobiletin group(P<0.001).(5)These findings suggest that nobiletin attenuates lipopolysaccharide-induced inflammatory response in BV2 microglia by suppressing nuclear factor-κB signaling pathway.