Curcumin Attenuates γ-ray Radiation Damage In GES-1 Cells By Down-regulating TLR4/NF-κB Signaling Pathway

[Objective]In this study,γ-ray irradiated normal Human Gastric Mucosal Epithelial cells(GES-1 cells)were used as in vitro model.To investigate whether the protective effect of Curcumin(CUR)on gastric radiation injury by down-regulating Toll like receptor 4(TLR4)/NF-κB(Nuclear factor kappa-B)signaling pathway,which provide a new research basis and theoretical basis for the treatment of gastric radiation-related diseases.[Methods]GES-1 cells were used in this study;combined with literature and previous studies,γ-ray(4Gy)was used for irradiation,and observation time was 24 hours after irradiation.1.Part I: Experimental grouping: Control group,irradiation group,irradiation +CUR 4μM group,irradiation +CUR 8μM group,irradiation+CUR 16μM group and single treatment group.The cell viability,inflammatory factor levels,TLR4 and NF-κB protein expression levels of GES-1 cells were detected by Methyl thiazolyl Tetrazolium(MTT),enzyme-linked immunosorbent assay(ELISA)and western blot(WB),respectively;To observe the effect of CUR on cell viability,inflammatory response,and TLR4/ NF-κB signal in GES-1 cells after γ-ray irradiation.2.Part II Experimental grouping: Control group,irradiation group,irradiation+CUR 16μM group,irradiation+CUR 16μM+LPS(TLR4/NF-κB agonist,1μg/m L)group,irradiation+CUR 16μM+TAK-242(TLR4/NF-κB inhibitor,1μM).To verify the mediating role of TLR4/NF-κB signaling pathway in the protective effect of CUR on GES-1 cells after radiation injury,the same markers were detected.[Results]1.Compared with the irradiated group,different concentrations of CUR(4,8,16μM)significantly enhanced the viability of GES-1 cells in a concentration-dependent manner,suggesting that CUR could alleviate theγ-ray radiation damage in GES-1 cells.2.Compared with the irradiated group,different concentrations of CUR(4,8,16μM)significantly inhibited the levels of TNF-α,IL-1β and IL-6 of GES-1 cells in a concentration-dependent manner,suggesting that CUR mitigated γ-ray-induced the up-regulation of inflammatory cytokines in GES-1 cells.3.Compared with the irradiation group,different concentrations of CUR(4,8,16μM)significantly down-regulated the protein expression levels of TLR4 and NF-κB of GES-1 cells in a concentration-dependent manner,suggesting that TLR4/NF-κB signaling pathway was involved in the protective effect of CUR on GES-1 cells against γ-ray radiation damage.4.Compared with irradiation +CUR(16μM)group,the expression levels of TLR4 and NF-κB of GES-1 cells were significantly up-regulated after LPS addition,while the expression levels of TLR4 and NF-κB of GES-1 cells were significantly inhibited after TAK-242 addition.These results indicated that LPS effectively up-regulated TLR4/NF-κB signaling pathway and TAK-242 effectively inhibited TLR4/NF-κB signaling pathway in this study.5.Compared with irradiation +CUR(16μM)group,the GES-1 cell viability was significantly decreased after LPS addition,while the GES-1cell viability was significantly increased after TAK-242 addition.The results showed that the addition of TLR4/NF-κB agonist reduced the protective effect of CUR on γ-ray radiation injury of GES-1 cells,and the addition of TLR4/NF-κB inhibitor enhanced the protective effect of CUR on γ-ray radiation injury of GES-1 cells.These results suggest that CUR reduced γ-ray radiation injury of GES-1 cells by down-regulating TLR4/NF-κB signaling pathway.6.Compared with irradiation +CUR(16μM)group,the levels of TNF-α,IL-1β and IL-6 in GES-1 cells were significantly increased after LPS addition,while the levels of TNF-α,IL-1β and IL-6 of GES-1 cells were significantly decreased after TAK-242 addition.The results showed that the addition of TLR4/NF-κB agonist reduced the inhibitory effect of CUR on inflammatory factors of GES-1 cells after γ-ray irradiation,and the addition of TLR4/NF-κB inhibitor enhanced the inhibitory effect of CUR on inflammatory factors of GES-1 cells after γ-ray irradiation.These results suggest that CUR inhibited inflammation to reduce γ-ray radiation damage in GES-1 cells by down-regulating the TLR4/NF-κB signaling pathway.[Conclusion] CUR inhibits inflammation by down-regulating the TLR4/NF-κB signaling pathway,thereby alleviating γ-ray radiation damage in GES-1 cells.