| Background:Ulcerative colitis(UC)is an immune disorder in colon,characterized by excessive activation of immune cells including macrophages and T cells,and consequently inflammation-induced tissue injury.Currently,traditional treatments of UC including salicylic acid,glucocorticoids and immunomodulator,exhibit suboptimal clinical efficacy and serious side effects.It is urgent to develop novel therapeutical strategies for UC management.Recently,ASM has been reported to regulate a variety of immune cell functions,and display pro-inflammatory activities.We hypothesize that ASM mediates immune responses of UC,and inhibition of ASM may protect mice against dextran sodium sulfate(DSS)-induced colitis.Objective:To explore the mechanism that ASM inhibitors including desipramine and amitriptyline regulate inflammatory responses of DSS colitis in mice.Methods:C57BL/6J mice were randomly divided into 4 groups: control,DSS,DSS+ desipramine,DSS+amitriptyline.The mice were free fed with 4% DSS solution from day 1 to day 7 to establish an acute colitis model.The mice of DSS+desipramine group and the DSS+amitriptyline group were treated with desipramine(20mg/kg body weight)and amitriptyline(20mg/kg body weight)intraperitoneally since day 3 to day 7.Disease activity index(DAI)was recorded daily until day 7.The mice were sacrificed on day 8.The histological changes as the parameter of inflammation in the colon were evaluated.The expression of ASM and pNF-?Bp65 in the tissues were detected by immunohistochemistry.ASM and MPO levels in the colon were measured.The levels of TNF,IL-1? and IL-10 were detected by ELISA.Results:1?The DAI score of DSS+amitriptyline group(7.33 ± 0.87)and DSS+desipramine group(7.00 ± 0.82)was lower than that of DSS group(P <0.05),and the control group DAI score was 0.30 ± 0.67(P <0.05).2?The histopathological score of DSS+amitriptyline group(4.78 ± 0.60)and DSS+desipramine group(4.80 ± 0.58)was lower than that of DSS group(P <0.05),and the histopathological score of control group was 0(P <0.05).3?MPO activity in DSS group was significantly higher than that in control group(P <0.001),and its activity was 14.23 ± 0.81U/g.The MPO activity of DSS+amitriptyline group(9.29±0.74U/g)and DSS+desipramine group(9.53±0.58U/g)was significantly lower than that of DSS group(P <0.001).4?The level of TNF in the DSS group was significantly higher than that in the control group(P <0.001).The levels of TNF expression in DSS+amitriptyline group(400.50±70.65pg/g)and DSS+desipramine group(415.0±82.82pg/g)were significantly lower than those in DSS group(P <0.001).5?The level of IL-1? expression in the DSS group was significantly higher than that in normal group(P <0.05).The expression of IL-1? in DSS+amitriptyline group(777.20±128.10pg/g)and DSS+desipramine group(813.10± 121.50pg/g)was significantly lower than that in DSS group(P <0.05).6?The expression of IL-10 in the DSS group was significantly lower than that in normal group(P <0.001).The expression of IL-10 in DSS+amitriptyline group(330.30±24.28pg/g)and DSS+desipramine group(330.60±30.42pg/g)was higher than that in DSS group(P <0.001).7?The mucosal and submucosal layers of DSS group contained a large number of ASM positive cells,the expression level was 7.28 ± 0.44.Control group had almost no ASM-positive cells compared with DSS group.The number of ASM positive cells in DSS+amitriptyline group(2.82±0.39)and DSS+desipramine group(2.62 ± 0.24)was significantly lower than that in DSS group(P <0.001).8?The expression of pNF-?B p65 in colonic tissue was significantly lower than that in control group(P <0.05).The number of pNF-?B p65 positive cells in DSS group was 70.50±3.17.DSS+amitriptyline group(38.76±6.03)and DSS+desipramine group(36.42±2.80)were significantly lower than the DSS group(P <0.001).9?The expression level of ASM in colon tissue of DSS group(124.40±14.85)was significantly higher than that in normal group.The expression of ASM in DSS+amitriptyline group(52.18±10.05)and DSS+desipramine group(65.01±11.91)was lower than that in DSS group(P <0.01).Conclusion:Inhibition of ASM by its inhibitors attenuates inflammatory response of DSS colitis in mice,likely through down-regulating of the ASM expression in intestinal tissue and inhibition of NF-?B activation. |
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