肠三叶因子对内毒素诱导幼鼠肠组织NO和MDA的作用

Effects of recombinant intestinal trefoil factor on endotoxin-induced expression of nitric oxide and malondialdehyde in intestinal tissues of infant rats

目的:探讨内毒素(LPS)致幼鼠肠组织NO、MDA的作用及基因重组肠三叶因子(recombinantintestinaltrefoilfactor,rITF)的保护作用.方法:Wistar幼鼠10日龄96只分为A组:生理盐水对照组,B组:LPS组,C组:LPS+rITF组,每组32只.以生理盐水(1mL/kg),EcoliO55:B5(1mL/kg)、5g/LrITF(0.1mL)ip后2,6,24,72h处死动物,留取肠组织生化法检测NO,MDA含量,PCR法检测诱导型一氧化氮合酶(iNOS)mRNA表达,同时作电镜观测肠组织超微结构变化.结果:B组NO和MDA含量明显高于A组,LPS作用后6,24h达高峰(NO24h:55.25±7.30vs6.25±2.05,P<0.01;MDA6h:7.60±1.14vs5.01±0.74,P<0.01).C组NO和MDA含量明显降低,其中6,24h组NO较B组下降,但仍高于A组,差异显著(P<0.05或P<0.01),至72h基本降至正常;6,24h组MDA含量较B组下降(P<0.01),较A组无差异,至72h基本降至正常.iNOSmRNA在A组各时间点均有微弱的表达,在B组6,24h时表达明显增强(1.17±0.15vs0.31±0.08,P<0.01;1.24±0.18vs0.30±0.05,P<0.01),较A组差异显著;而C组2,72hiNOSmRNA微弱表达,6,24h时表达明显减少(0.91±0.13,0.96±0.15),较B组差异显著(P<0.01).B组超微结构改变明显,而C组较B组超微结构有不同程度减轻.结论:LPS可致幼鼠肠组织NO和MDA含量增加及诱导iNOSmRNA表达增加,rITF可抑制iNOSmRNA表达而减少NO含量,同时降低MDA含量,发挥对肠损伤的保护作用.

AIM： To investigate the effects of recombinant intestinal trefoil factor （rITF） on the expression of nitric oxide （NO） and malondialdehyde （MDA） induced by lipopolysaccharide （LPS） in infant rats. METHODS： Ninety-six 10-day-old Wistar rats were divided into 3 groups. The rats in group A served as normal controls and were injected with normal saline （1 mL/kg） intraperioneaUy. The rats in group B and C were intraperioneally treated with LPS （1 mL/kg） and LPS （1 mL/kg） plus rlTF （5 g/L, 0.1 mL）, respectively. Intestinal tissues were collected at 2, 6, 24, and 72 h for the examination of NO, MDA productions, iNOS mRNA expression and intestinal histological changes. RESULTS： In comparison with group A, the NO and MDA contents were significantly increased in Group B and reached the peak 6 or 24 h after LPS administration （NO 24 h： 55.25 ±7.30 vs 6.25 ± 2.05, P 〈 0.01; MDA 6 h： 7.60 ± 1.14 vs 5.01 ± 0.74, P 〈 0.01） respectively. As compared with group B, the NO were decreased in group C （P 〈 0.05 or P 〈 0.01）, but still sustained a higher level than that in group A at 6 and 24 h, which attained normal at 72 h; the content of MDA were decreased than that in group B （P 〈 0.01） and had no discrepancy with that in group A （P 〉 0.05） at 6 and 24 h. iNOS mRNA was weakly expressed in group A, but significantly increased in group B at 6 and 24 h （1.17 ± 0.15 vs 0.31 ± 0.08, P 〈 0.01; 1.24 ± 0.18 vs 0.30 ± 0.05, P 〈 0.01）. The expression of iNOS mRNA at 6 and 24 h in group C （0.91 ± 0.13, 0.96 ± 0.15） was markedly decreased that that in group B （P 〈 0.01）. The pathological changes in group C alleviated notably than those in group B. CONCLUSION： LPS can induce the increase of NO, MDA and expression of iNOS mRNA in intestinal tissues of infant rats, and rITF can protect intestine against injury through decreasing the contents of NO and MDA and inhibiting the expression of iNOS mRNA.