目的 探讨微小RNA-155（miRNA-155）是否通过调控核苷酸结合寡聚化结构域蛋白1（NOD1）/核因子κB（NF-κB）信号通路在新生大鼠缺氧、缺血性脑损伤中发挥作用。  方法 选择新生雄性大鼠40只，分4组，每组10只。分别是假手术组、缺氧缺血组（HI组）、阴性对照组（NC antagomir组）、miRNA-155抑制组（miRNA-155 antagomir组）。大鼠经10%水合氯醛（400 mg/kg）麻醉后取左脑测定脑组织含水量；采用HE染色，于光学显微镜下观察各组大鼠脑海马组织病理形态学改变；采用Western blotting法检测各组大鼠脑组织中NOD1、NF-κB p65、NF-κB p50、磷酸化NF-κB p65（p-NF-κB p65）和p-NF-κB p50的蛋白表达水平；采用Real-time PCR法检测各组大鼠脑组织及血清中miRNA-155、NOD1、NF-κB p65和NF-κB p50的mRNA表达水平。  结果 与假手术组相比，HI组和NC antagomir组新生大鼠脑组织含水量显著升高，miRNA-155 antagomir组显著降低（P＜0.05）；假手术组海马细胞排列整齐，细胞形态结构及层次清晰完整，无空泡，间质无水肿；HI组和NC antagomir组可见海马细胞排列紊乱，形成空泡，胶质细胞增生，细胞间隙增宽出现水肿，坏死细胞数增多；miRNA-155 antagomir组脑组织水肿明显减轻，海马细胞排列紊乱现象有所改善，坏死细胞数减少。与假手术组相比，HI组和NC antagomir组新生大鼠NOD1、p-NF-κB p65和p-NF-κB p50蛋白表达水平显著升高，而miRNA-155 antagomir组与HI组和NC antagomir组相比显著降低，差异均具有统计学意义（P＜0.05）；HI组和NC antagomir组新生大鼠脑组织及血清NOD1 mRNA表达水平显著高于假手术组，miRNA-155 antagomir组NOD1 mRNA表达水平与HI组和NC antagomir组相比显著降低（P＜0.05），但各组大鼠NF-κB p65及NF-κB p50的表达水平差异无统计学意义（P＞0.05）。  结论 MiRNA-155可通过调控NOD1/NF-κB信号通路促进新生大鼠缺氧、缺血性脑损伤，其作用机制可能与miRNA-155激活NOD1信号通路，促进下游NF-κB发生磷酸化，加剧缺氧、缺血新生乳大鼠脑组织炎症。

Objective To investigate if microRNA(miRNA)-155 intensifys hypoxic-ischemic brain injury in neonatal rats by regulating nucleotide-binding oligomerization domains 1 (NOD1)/ nuclear factor κB (NF-κB) signaling pathway.   Methods Forty neonatal male rats were selected and divided into four groups with 10 rats in each group. They were sham operated group, hypoxic-ischemic group (HI group), negative control group (NC antagomir group), miRNA-155 inhibition group (miRNA-155 antagomir group). After 10% chloral hydrate (400 mg/kg) anesthesia, the left brain of rats was taken and the water content of brains tissue were measured. Histopathological changes of hippocampus and cortex were observed under light microscope by HE staining. Western blotting method  was used to detect the expression levels of NOD1, NF-κB p65, NF-κB p50, phosphorylated NF-κB p65 (p-NF-κB p65) and p-NF-κB p50 in brain tissues of rats in each group. The mRNA expression levels of miRNA-155, NOD1, NF-κB p65 and NF-κB p50 in brain tissue and serum of rats were detected by Real-time PCR.  Results  Compared with the sham operated group, the brain water content of neonatal rats in HI group and NC antagomir group increased significantly, and that in miRNA-155 antagomir group decreased significantly (P<0.05). The hippocampal cells in sham operated group were arranged neatly, with clear and complete cellular structure and hierarchy, no vacuoles and no edema in the stroma were observed. The hippocampal cells in HI group and NC antagomir group arranged disorderly, forming vacuoles, glial cell proliferation, cell gap widening, edema and more necrotic cells were observed. In the group of miRNA-155 antagomir, brain edema was significantly alleviated, hippocampal cell disorder was improved, and the number of necrotic cells was reduced. Compared with sham-operated group, the protein expression levels of NOD1, p-NF-κB p65 and p-NF-κB p50 in HI group and NC antagomir group were significantly higher, while the expression levels of miRNA-155 antagomir group were significantly lower than those in HI group and  NC antagomir group (P<0.05). The expression level of NOD1 in brain tissue and serum of neonatal rats in HI group and NC antagomir group was significantly higher than that in sham operated group. The expression level of NOD1 in miRNA-155 antagomir group was significantly lower than that in HI group and NC antagomir group (P<0.05), but there was no significant difference in the expression levels of NF-κB p65, NF-κB p50 among the groups (P>0.05).  Conclusion MiRNA-155 can promote hypoxic-Ischemic brain injury in neonatal rats by regulating NOD1/NF-κB signaling pathway. Its mechanism may be related to the activation of NOD1 signaling pathway by miRNA-155, the phosphorylation of downstream NF-κB, and increased brain inflammation in neonatal rats with hypoxic-ischemia.