Objective To establish an appropriate neonatal rat model with necrotizing enterocolitis (NEC) and to investigate the protective effects of interleukin-1 receptor associated kinase (IRAK) 1/4 inhibitor on intestinal tissue of neonatal rats with NEC.Methods Thirty-six newborn SD rats were randomly divided into normal control group,NEC model group and IRAK1/4 inhibitor group,12 rats in each group.The rats in normal control group were raised by their mother and they did not receive any intervention.The rats of NEC model group were given artificial feeding,under hypoxia and cold stress.The IRAK1/4 inhibitor group were given IRAK1/4 inhibitor intervention,and also given artificial feeding,under hypoxia and cold stress.Three days later,all rats were sacrificed and intestinal tissues were obtained.The histopathological changes in ileocecal tissues were evaluated by pathological score after hematoxylin-eosin staining.The levels of interleukin (IL)-1β,IL-6 and tumor necrosis factor (TNF)-α in intestinal tissues were detected by enzyme-linked immunosorbent assay.Results The rats of NEC model group presented abdominal distention,diarrhea (partly with mucous bloody stool),decreased activity,poor response,lethargy and other symptoms,and the extent was gradually worsened;the rats in IRAK1/4 inhibitor group also had abdominal distention,diarrhea,decreased activity,poor response and other symptoms,but the symptoms emerged later and milder.The histopathological score of intestinal tissues of normal control group was (0.33 ± 0.49) scores,NEC model group was (3.08 ± 0.99) scores,and IRAK1/4 inhibitor group was (1.75 ±0.96) scores.The histopathological scores of NEC model group and IRAK1/4 inhibitors group were significantly higher than those in normal control group (all P ＜ 0.01),and the histopathological scores of IRAK1/4 inhibitor group were significantly lower than those in the NEC model group (P ＜ 0.01).The levels of IL-1β,IL-6 and TNF-α in normal control group separately were (128.76 ± 27.25) ng/L,(0.41 ± 0.10) ng/L,(6.93 ± 1.79) ng/L,respectively;the levels of NEC model group separately were (410.99 ± 44.16) ng/L,(1.79 ± 0.18) ng/L,(44.39 ± 6.00) ng/L;the levels of IRAK1/4 inhibitor group separately were (256.23 ±41.29) ng/L,(1.05 ±0.19) ng/L,(21.45 ± 6.36) ng/L,respectively.The levels of IL-1β,IL-6 and TNF-α of NEC model group had significant differences compared with those of normal control group,respectively (all P ＜0.01);the levels of IL-1β3,IL-6 and TNF-α of IRAK1/4 inhibitor group had significant differences compared with those of normal control group,respectively (all P ＜ 0.01);the levels of IL-1β,IL-6 and TNF-α of IRAK1/4 inhibitor group had significant differences compared with those of NEC model group (all P ＜ 0.01),respectively.Conclusions IRAK1/4 inhibitor has some protective effects on the intestinal tissues of neonatal rats with NEC,which can reduce the damage to the intestinal tissues,and decrease the secretion of inflammatory cytokines like IL-1β,IL-6 and TNF-α.%目的 建立坏死性小肠结肠炎(NEC)新生大鼠模型,探讨白细胞介素-1受体相关激酶(IRAK)1/4抑制剂对NEC新生大鼠肠道的保护作用.方法 36只新生SD大鼠分为正常对照组、NEC模型组和IRAK1/4抑制剂组,每组12只.正常对照组新生大鼠与母鼠同窝进行母乳喂养,不做任何干预;NEC模型组新生大鼠给予代鼠乳人工喂养,并进行缺氧及冷刺激;IRAK1/4抑制剂组新生大鼠给予IRAK1/4抑制剂干预,同时进行代鼠乳人工喂养+缺氧+冷刺激.3d后处死大鼠取出肠道组织,苏木精-伊红染色后对回盲部肠道组织进行病理评分.酶联免疫吸附试验检测肠道组织中白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)及肿瘤坏死因子-α(TNF-α)的表达水平.结果 NEC模型组新生大鼠逐渐出现腹胀、腹泻(部分见黏液血便)、活动减少、反应差、嗜睡等表现,程度逐渐加重;IRAK1/4抑制剂组新生大鼠也逐渐出现腹胀、腹泻、活动减少、反应差等表现,但出现时间较晚,程度较轻.肠组织病理评分:正常对照组为(0.33±0.49)分,NEC模型组为(3.08±0.99)分,IRAK1/4抑制剂组为(1.75±0.96)分,NEC模型组及IRAK1/4抑制剂组均较正常对照组明显升高,差异均有统计学意义(均P＜0.01),IRAK1/4抑制剂组与NEC模型组比较差异有统计学意义(P＜0.01).各组大鼠肠道IL-1β、IL-6和TNF-α水平:正常对照组分别为(128.76±27.25) ng/L、(0.41±0.10) ng/L和(6.93±1.79) ng/L;NEC模型组分别为(410.99±44.16) ng/L、(1.79±0.18) ng/L和(44.39±6.00) ng/L;IRAK1/4抑制剂组分别为(256.23±41.29) ng/L、(1.05±0.19) ng/L和(21.45±6.36) ng/L.NEC模型组IL-1β、IL-6和TNF-α水平与正常对照组比较,差异均有统计学意义(均P＜0.01);IRAK1/4抑制剂组IL-1β、IL-6和TNF-α水平与正常对照组比较,差异均有统计学意义(均P＜0.01);IRAK1/4抑制剂组IL-1β、IL-6和TNF-α水平与NEC模型组进行比较,差异均有统计学意义(均P＜0.01).结论 IRAK1/4抑制剂对NEC新生大鼠的肠道具有保护作用,能够减轻肠道的损伤,减少IL-1β、IL-6和TNF-α等炎性细胞因子的释放.
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