Expression and function of interleukin-23/17 axis in trinitrobenzene sulphonic acid induced colitis in mouse / 中华消化杂志

ABSTRACT

Objective To study the expression and the role of interleukin (IL)-23/IL-17 axis in colonic tissue of trinitrobenzene sulphonic acid (TNBS) induced eolitic mice.Methods Mice were divided into four groupscontrol (n=24),TNBS (n= 24),TNBS 48 hours + mlL-17 antibodies (n=24),TNBS 48 hours + normal rat blood-serum (n= 24).TNBS-induced colitis model was constructed.The mice in control group and TNBS colitis group were sacrificed at 24 hours,48 hours,7th day,respectively.In TNBS 48 hours + mlL-17 antibodies group and TNBS 48 hours + normal rat blood-serum group,a single injection with the polyclonal mlL-17 antibodies or serum were given intraperitoneally at two hours before enema with TNBS,respectively,and the mice were killed at 48 hours after enema with TNBS.The histological score of colon and myeloperoxidase (MPO) activity of colonic tissue were evaluated in each group.IL-23p19 and IL-17 concentrations in colonic tissue were measured by enzyme-linked immunosorbent assay (ELISA).Expression of nuclear factor (NF)-κBp65in colonic tissue was detected by immunohistochemistry method.Expression of IL-23p19,IL-17 and IL-12p35 mRNA in colonic tissue were detected by real-time fluorescent quantitative reverse transcriptase polymerase chain reaction (RT-PCR) with SYBR Green I.Results The protein levels of IL-23p19 in colonic tissue in TNBS colitis groups at 24 hours,48 hours and 7 days were (15.53±3.32),(31.16±4.98) and (14.03±3.56) ng/mg,respectively,and their mRNA level were (4.09±0.34),(3.39±0.46) and (6.54±1.82),respectively.The protein levels of IL-17 were (0.35±0.06),(0.38±0.08),and (0.26±0.05) ng/mg,respectively,and their mRNA level were (4.21±2.61),(2.65±0.91) and (5.63±1.43),respectively.The expression levels of IL-23p19 and IL-17 in colitis model were significantly higher than those in control group and the peak was at 48 hours.Moreover,expression of IL-23p19 and IL-17 and their mRNA were positively correlated to their mRNA levels.In TNBS 48 hours + mIL-17 antibodies group,the expression levels of NF-κBp65,the microscopic scores and MPO (1.86 % ± 0.36 %,0.63 ± 0.52,0.40 ± 0.03 U/g,respectively) were significantly lower than those in TNBS 48 hours group (4.35% ±0.37%,5.13±0.64,2.29±0.40 U/g tissue,respectively).Neutralization of IL-17 was significantly protected against TNBS-induced colonic inflammation and MPO and expression of NF-κB p65.The results indicated that neutralization of IL-17 significantly reduced colonic inflammation and suppressed NF-κBp65 activation.This protection occurred in the presence of equivalent induction of local IL-23 p19 and high levels of IL-12p35 in the polyclonal raiL-17 antibodies-treated mice.Conclusions IL-23/IL-17 axis plays a critical role at the early acute phase of TNBS-induced inflammation.IL-17 may represent a new target for therapeutic intervention for inflammatory bowel disease.