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目的探讨孕期维生素A(VA)缺乏对LPS诱导的仔鼠肠上皮屏障功能障碍的影响。方法构建孕期开始的VA正常(VAN)和VA缺乏(VAD)母鼠模型,其子代(仔鼠)于6周龄时给予脂多糖(LPS)灌胃诱导肠道感染。高效液相色谱法(HPLC)检测血清视黄醇水平;ELISA试剂盒检测仔鼠血清二胺氧化酶(DAO)浓度;采用RT-PCR和Western blot技术测定RA受体(RARβ)、Toll样受体4和紧密连接蛋白ZO-2的变化。结果 VA营养水平与LPS处理均是血清视黄醇的影响因素(P<0.000 1和P=0.035 9),但影响血清视黄醇水平的主要因素是VA营养水平(P<0.000 1)。同时,VA水平与LPS处理也均是血清DAO水平的影响因素(P=0.048 1和P<0.000 1),但LPS是引起DAO水平升高的主要因素(P<0.000 1)。此外,VAD仔鼠结肠黏膜组织中的RARβ、TLR4和ZO-2的mRNA和蛋白表达水平均较VAN组显著降低。LPS处理后,RARβ的表达水平在VAN组进一步降低,VAD仔鼠结肠黏膜组织中TLR4和ZO-2的表达水平始终低于VAN组。结论孕期开始的持续的VA缺乏主要降低血清视黄酸水平及ZO-2的表达,LPS处理上调血清DAO水平及肠上皮细胞TLR4的表达,而RARβ的表达水平受到VAD及LPS的交互作用,提示VA缺乏可能会降低仔鼠肠道的天然免疫调节能力,降低肠道屏障功能,从而影响肠道的抗感染能力。
Objective To investigate the effect of vitamin A (VA) deficiency during pregnancy on intestinal dysfunction induced by LPS in neonatal rats. Methods VAM and VA deficiency female rats were established during the first trimester of pregnancy. Offspring of offspring were fed with lipopolysaccharide (LPS) at the age of 6 weeks to induce intestinal infection. Serum retinol levels were determined by high performance liquid chromatography (HPLC). Serum diamine oxidase (DAO) concentrations were measured by ELISA kit. RA receptor (RARβ), Toll-like receptor Body 4 and the tight junction protein ZO-2 changes. Results Both VA nutrition level and LPS treatment were the influencing factors of serum retinol (P <0.000 1 and P = 0.035 9). However, the main factor affecting the serum retinol level was VA nutrition level (P <0.000 1). At the same time, VA level and LPS treatment were also the influencing factors of serum DAO level (P = 0.048 1 and P <0.000 1). However, LPS was the main factor causing the increase of DAO level (P <0.000 1). In addition, mRNA and protein expression of RARβ, TLR4 and ZO-2 in colonic mucosa of VAD rats were significantly lower than those in VAN group. After LPS treatment, the expression of RARβ was further decreased in VAN group. The expression of TLR4 and ZO-2 in colonic mucosa of VAD rats was always lower than that of VAN group. CONCLUSION: The persistent VA deficiency during pregnancy reduces serum retinoic acid level and ZO-2 expression. LPS treatment up-regulates serum DAO level and intestinal epithelial TLR4 expression, while the level of RARβ is influenced by VAD and LPS VA deficiency may reduce the innate immune regulatory capacity in the intestinal tract of the offspring, reduce intestinal barrier function, thus affecting the intestinal anti-infective ability.