Objective: To investigate the role of miRNA-210 in hypoxic-ischemic brain edema in neonatal rats.
Methods: A total of 80 neonatal rats were randomly divided into control group, normal saline group, miRNA-210 expression inhibition group, and miRNA-210 overexpression group, with 20 rats in each group. Each group was randomly divided into sham-operation group and hypoxia-ischemia (HI) group, with 10 rats in each group. The neonatal rats in the HI group were treated with ligation of the left common carotid artery and then put in a hypoxia cabin with mixed gas of 8% O2 and 92% N2 for 2 hours; those in the sham-operation group were treated with isolation of the left common carotid artery only, without ligation or hypoxia treatment. After HI or sham-operation, the rats in the normal saline group, miRNA-210 expression inhibition group, and miRNA-210 overexpression group were intracranially injected with normal saline (2.5 mg/kg), miRNA-210 inhibitor (2.5 mg/kg), and miRNA-210 mimic (2.5 mg/kg) respectively. No treatment was given to the rats in the control group. The rats were sacrificed three days later, and the left brain tissue was harvested. Fluorescent quantitative PCR was used to measure the expression of miRNA-210; the dry-wet weight method was used to measure the water content of brain tissue; hematoxylin and eosin staining was used to observe the histomorphological changes in the brain.
Results: The HI groups showed significant reductions in the expression of miRNA-210 and significant increases in the water content of brain tissue compared with the corresponding sham-operation groups (P<0.05). Compared with the normal saline HI group, the miRNA-210 expression inhibition HI group showed a significant reduction in the expression of miRNA-210 and a significant increase in the water content of brain tissue (P<0.05), and the miRNA-210 overexpression HI group showed a significant increase in the expression of miRNA-210 and a significant reduction in the water content of brain tissue (P<0.05). The results of hematoxylin and eosin staining suggested that the miRNA-210 expression inhibition HI group showed marked edema, and the miRNA-210 overexpression HI group showed a significant improvement in edema.
Conclusions: Neonatal rats show down-regulated expression of miRNA-210 after HI, suggesting that miRNA-210 may be involved in the development and progression of hypoxic-ischemic brain edema in neonatal rats.
目的: 探讨miRNA-210在新生大鼠缺氧缺血性脑水肿中的作用。
方法: 将80只新生大鼠随机分为对照组、生理盐水组、miRNA-210表达抑制组及miRNA-210过表达组，每组20只；各组大鼠再随机分为假手术组及缺氧缺血（HI）组，每组10只。HI组新生大鼠结扎左侧颈总动脉后，置于8% O2和92% N2的混合气体缺氧舱中持续2h；假手术组仅游离左侧颈总动脉，但不予结扎和缺氧处理。HI或假手术术后，分别向生理盐水组、miRNA-210表达抑制组和miRNA-210过表达组大鼠颅内注射生理盐水（2.5mg/kg），miRNA-210 incubitor（2.5mg/kg）和miRNA-210 minic（2.5mg/kg），对照组大鼠不予任何处理。3d后断头，取左侧脑组织，采用荧光定量PCR方法检测miRNA-210的表达；采用干湿质量法检测脑组织含水量；苏木精-伊红染色观察脑组织形态学改变。
结果: 各组HI新生大鼠脑组织中miRNA-210的表达较相应假手术组均显著下调，脑组织含水量显著上调（P < 0.05）。与生理盐水HI组比较，miRNA-210表达抑制HI组中miRNA-210的表达显著下调，脑组织含水量显著上调（P < 0.05）；miRNA-210过表达HI组中miRNA-210的表达显著上调，脑组织含水量显著下调（P < 0.05）。苏木精-伊红染色结果提示miRNA-210表达抑制HI组水肿改变明显；miRNA-210过表达HI组水肿改变明显改善。
结论: 新生大鼠脑HI后miRNA-210表达下调，可能参与了新生大鼠缺氧缺血性脑水肿的发生发展。