Objective: To investigate the protective effect of L. reuteri DSM17938 strain against oxidative stress in a neonatal mouse model of necrotizing enterocolitis (NEC) and explore the possible mechanism.
Methods: Ninety-six 10-day-old neonatal C57BL/6J mice were equally randomized into control group, NEC group, and NEC+ L. reuteri group. The pathological changes of the ileocecal intestinal tissue were evaluated with HE staining and double-blind pathological scoring. The mRNA and protein expressions of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in the intestinal tissues were detected using quantitative real-time PCR and ELISA, respectively. Colorimetric assays were used to determine the activity of superoxide dismutase (SOD) and its inhibition rate, malondialdehyde (MDA), glutathione (GSH), oxidized glutathione (GSSG), and GSSG/ GSH ratio.
Results: Compared with those in the control group, the neonatal mice in NEC group showed significant weight loss (P < 0.05), obvious intestinal injury, increased pathological scores (P < 0.05), increased expressions of TNF-α and IL-1β mRNA and proteins (P < 0.05), decreased SOD activity and inhibition rate, decreased GSH, and significantly increased MDA, GSSG, and GSSG/GSH ratios (P < 0.05). Treatment with L. reuteri obviously decreased the pathological scores, expressions of TNF-α and IL-1β (P < 0.05), MDA, GSSG, and GSSG/GSH ratio (P < 0.05), and significantly increased SOD activity, its inhibition rate, and GSH level in the mice with NEC, but the survival rate was not significantly different between NEC and L. reuteri-treated groups (P > 0.05).
Conclusions: L. reuteri DSM17938 can offer protection against NEC in mice by reducing oxidative stress and increasing antioxidant capacity of the intestinal tissue to suppress intestinal inflammations.
目的: 探讨罗伊氏乳杆菌（L. reuteri）DSM17938菌株对坏死性小肠结肠炎（NEC）新生小鼠模型氧化应激的保护作用及可能机制。
方法: 将96只10日龄C57BL/6J新生小鼠随机分为3组（n=32）：对照组、NEC组、NEC+L. reuteri组。通过HE染色观察回盲部肠组织病理变化并行双盲病理评分。采用实时荧光定量PCR检测肠组织中TNF-α、IL-1β的基因表达水平。通过ELISA检测肠组织TNF-α、IL-1β的蛋白表达水平。采用比色法检测SOD活力及抑制率、MDA、GSH、GSSG、GSSG/GSH比值。
结果: 与对照组相比，NEC组小鼠体质量下降（P < 0.05），肠道损伤加重，病理评分增加（P < 0.05），TNF-α、IL-1β在基因及蛋白水平均表达升高（P < 0.05），SOD活力及抑制率、GSH降低，MDA、GSSG、GSSG/GSH比值显著升高（P < 0.05）。与NEC组相比，NEC+L. reuteri组病理评分降低，TNF-α、IL-1β在基因及蛋白水平均表达降低（P < 0.05），SOD活力及抑制率、GSH增加，MDA、GSSG、GSSG/GSH比值明显降低（P < 0.05），两组生存率差异无统计学意义（P > 0.05）。
结论: L. reuteri DSM17938可能通过减少肠道氧化应激、增加其抗氧化能力，从而减轻肠道炎症反应，发挥对NEC新生小鼠肠道保护作用。
Keywords: Lactobacillus reuteri DSM17938; inflammatory cytokines; necrotizing enterocolitis; oxidative stress.