Effects of ε-polylysine and pectin on intestinal mucosal barrier in mice with ulcerative colitis
Objective To construct mice models of ulcerative colitis(UC),and to investigate the effects of e-polylysine,pectin and their mixture on intestinal mucosal barrier in UC mice and its potential mechanism.Methods Forty male BALB/c mice were randomly divided into control group,UC group,ε-polylysine group,pectin group and ε-polylysine+pectin group,with 8 mice each.All mice were pretreated by gavage:control group and UC group were given 20 mL/(kg·d)of drinking water,e-polylysine group was given 10 mg/(kg·d)of ε-polylysine,pectin group was given 200 mg/(kg·d)of pectin,and ε-polylysine+pectin group was given 10 mg/(kg·d)and 200 mg/(kg·d)pectin.After 4-week gavage,the mice in UC group,ε-polylysine group,pectin group and ε-polylysine+pectin group drank 3％dextroan sulfate solution freely for 9 d to construct UC models,and the mice in control group drank drinking water freely for 9 d.After modeling,the disease activity index(DAI)score was evaluated,the length of the colon was measured,and the pathological morphology of the colon was observed by HE staining method.The serum tumor necrosis factor-α(TNF-α)and interleukin-6(IL-6)levels were detected by ELISA.Real-time fluorescence quantitative PCR was used to detect the relative expressions of occludin and zonula occludens-1(ZO-1)mRNAs.Western blot assay was used to detect the relative expressions of Toll-like receptor 4(TLR4),nuclear factor-κB p65(NF-κB p65)and p-NF-κB p65 proteins,and p-NF-κB p65/NF-κB p65 was calculated.Results(1)The DAI score was higher in UC group(6.75±1.91),ε-polylysine group(5.75±1.75),pectin group(3.00±0.76)and ε-polylysine+pectin group(6.00±3.21)than that in control group(0)(P＜0.05),was higher in UC group and ε-polylysine+pectin group than that in pectin group(P＜0.05),showed no significant difference between ε-polylysine group and pectin group(P＞0.05),and among UC group,ε-polylysine group and ε-polylysine+pectin group(P＞0.05).The colon length was shorter in UC group[(6.96±0.78)cm]and ε-polylysine+pectin group[(6.79±0.73)cm]than that in control group[(8.10±0.55)cm](P＜0.05),showed no significant difference in ε-polylysine group and pectin group compared with control group(P＞0.05),was shorter in UC group and ε-polylysine+pectin group than that in pectin group(P＜0.05),and showed no significant difference between ε-polylysine group and pectin group(P＞0.05),and among UC group,ε-polylysine group and ε-polylysine+pectin group(P＞0.05).(2)In control group,the mucosal epithelium structure of colon tissue was intact,the glands were arranged neatly,and the crypts were normal.In UC group,the mucosal epithelium structure was incomplete,inflammatory cells infiltrated more than 2/3 of the mucosal layer,mainly lymphocytes infiltrated,the lesion scope was more than 50％,and 2/3 of the basal layer recess was destroyed.Compared with UC group,the mucosal epithelium structure of ε-polylysine group was intact,the inflammatory cells infiltrated more than 1/3 of the mucosal layer,the lesion range was greater than 25％,and 1/3 of the basal layer recess was destroyed;the mucosal epithelium structure of pectin group was more complete,the inflammatory cells infiltrated the mucosal layer less than 1/3,and the lesion scope and the degree of recess destruction were significantly reduced.Compared with pectin group,inflammatory cell infiltration increased in ε-polylysine+pectin group,and the lesion extent and crypt destruction degree enlarged.(3)The serum TNF-α level was higher in UC group,ε-polylysine group and ε-polylysine+pectin group than that in control group and pectin group(P＜0.05),and showed no significant difference between pectin group and control group(P＞0.05)and among UC group,ε-polylysine group and ε-polylysine+pectin group(P＞0.05).The serum IL-6 level was higher in UC group and ε-polylysine+pectin group than that in control group(P＜0.05),was lower in ε-polylysine group and pectin group than that in UC group(P＜0.05),and showed no significant difference in ε-polylysine group and pectin group compared with control group(P＞0.05),between ε-polylysine+pectin group and UC group(P＞0.05),and among ε-polylysine group,pectin group and ε-polylysine+pectin group(P＞0.05).(4)The relative expressions of occludin and ZO-1 mRNAs were lower in UC group and ε-polylysine+pectin group than those in control group and pectin group(P＜0.05),and showed no significant differences in ε-polylysine group and pectin group compared with control group,between ε-polylysine group and pectin group and among UC group,ε-polylysine group and ε-polylysine+pectin group(P＞0.05).(5)The relative expression of TLR4 protein was higher in UC group and ε-polylysine+pectin group than that in control group(P＜0.05),showed no significant difference in ε-polylysine group and pectin group compared with control group(P＞0.05).The p-NF-κB p65/NF-κB p65 was higher in UC group,ε-polylysine group andε-polylysine+pectin group than that in control group(P＜0.05),and showed no significant difference between pectin group and control group(P＞0.05).The relative expression of TLR4 protein and the p-NF-κB p65/NF-KB p65 were higher in UC group and ε-polylysine+pectin group than those in pectin group(P＜0.05),and showed no significant differences between ε-polylysine group and pectin group(P＞0.05).There were no significant differences in the relative expression of TLR4 protein and the p-NF-κB p65/NF-κB p65 among UC group,ε-polylysine group and ε-polylysine+pectin group(P＞0.05).Conclusion Pectin can prevent UC in mice by inhibiting TLR4/NF-κB signaling pathway,reducing colon tissue inflammation and protecting intestinal mucosal barrier,while ε-polylysine can weaken the protective effect of pectin on intestinal mucosal barrier in UC mice.
NETL
NSTL
万方数据
