Study on the inhibitory effect of pachymaric acid on the inflammatory response of intestinal epithelial cells induced by Fusobacterium nucleatum and its mechanism
Objective To investigate the effect of pachymic acid(PA)on HIEC-6 inflammatory response of intestinal epithelial cells infected by Fusobacterium nucleatum(Fn)and its possible mechanism.Methods HIEC-6 cells were divided into control group,model group(1× 108 CFU·mL-1 Fn infection),experimental-L group(1× 108 CFU·mL-1 Fn+2 μmol·L-1 PA),experimental-M group(1× 108CFU·mL-1 Fn+4 μmol·L-1 PA),experimental-H group(1× 108 CFU·mL-1 Fn+8 μmol·L-1 PA),pcDNA-TLR4 group(1 × 108 CFU·mL-1 Fn+8 μmol·L-1 PA+transfected pcDNA-TLR4).After 12 h of treatment,the cell proliferation was detected by cell counting kit-8(CCK-8)test and Edu test respectively.The expression of inflammatory cytokines was detected by enzyme-linked immunosorbent assay(ELISA)and real-time quantitative polymerase chain reaction(RT-qPCR)respectively.The apoptosis was detected by flow cytometry.Western blot assay was used to detect the expression level of cell related proteins.Results The apoptosis rates of control,model,experimental-L,experimental-M,experimental-H and pcDNA-TLR4 groups were(3.51±0.31)%,(23.38±1.85)%,(16.74±0.54)%,(12.10±1.44)%,(8.89±0.63)%and(14.87±0.88)%,respectively;IL-8 content were(23.25±1.41),(79.69±4.37),(68.94±2.63),(51.46±2.56),(34.18±2.63)and(71.09±5.08)pg·mL-1,respectively;IL-1β contents were(8.81±0.49),(51.65±2.13),(35.98±3.47),(24.83±2.47),(14.79±1.25)and(43.89±1.59)pg·mL-1.Compared between model group and control group,compared between experimental-L,experimental-M,experimental-H groups and model group,compared between pcDNA-TLR4 group and experimental-H group,the differences of the above indexes were all statistically significant(all P<0.05).Conclusion Pachymaric acid may improve the apoptosis of Fn infected intestinal epithelial cells by inhibiting TLR4/NF-κB pathway and inflammatory response.