Hypoxic-ischemic brain damage (HIBD) represents one of the leading causes of neonatal mortality and permanent neurological disability worldwide. Compelling studies have identified implication of microRNAs (miRNAs) in HIBD. However, the molecular mechanism of miR-21 underlying the disease pathogenesis is unknown. The present study aims to explore the role of miR-21 in neonatal rats with HIBD. HIBD rat models were developed by carotid artery ligation and hypoxia treatment, and in vitro cell models were induced by oxygen-glucose deprivation. Through RT-qPCR and western blot analysis, high expression of CCL3 and poor expression of miR-21 were detected in brain tissues of rats with HIBD. Results of dual-luciferase reporter gene assay demonstrated that miR-21 could target and downregulate CCL3. The effect of miR-21 on the neurobehavioral ability of rats, the pathological characteristics of brain tissues, neuron apoptosis and as well as its impact on the NF-κB signaling pathway-related factors was examined by gain- and loss-of-function experiments. The obtained data suggested that upregulation of miR-21 resulted in significantly reduced cerebral infarct volume and degree of brain tissue damage, and improved neurobehavioral ability and memory ability in rats with HIBD through downregulation of CCL3. Besides, overexpression of miR-21 downregulated CCL3 to repress IKKα/β and p65 phosphorylation both in vivo and in vitro, hence disrupting the NF-κB signaling pathway. Taken together, the key findings of the current study underlie the cerebral protective effect of miR-21 against HIBD in neonatal rats through the inhibition of CCL3.

中文翻译：

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miR-21通过靶向CCL3保护新生大鼠免受缺氧缺血性脑损伤。

缺氧缺血性脑损伤（HIBD）代表了全球新生儿死亡和永久性神经系统残疾的主要原因之一。引人入胜的研究已经确定了HIBD中microRNA（miRNA）的含义。但是，miR-21发病机理的分子机制尚不清楚。本研究旨在探讨miR-21在HIBD新生大鼠中的作用。通过颈动脉结扎和缺氧处理建立HIBD大鼠模型，并通过氧葡萄糖剥夺诱导体外细胞模型。通过RT-qPCR和蛋白质印迹分析，在HIBD大鼠的脑组织中检测到CCL3的高表达和miR-21的低表达。双荧光素酶报告基因检测结果表明，miR-21可以靶向并下调CCL3。miR-21对大鼠神经行为能力的影响，通过功能获得性和丧失性功能实验研究了脑组织的病理学特征，神经元凋亡及其对NF-κB信号通路相关因子的影响。获得的数据表明，miR-21的上调可通过下调CCL3来显着降低HIBD大鼠的脑梗死体积和脑组织损伤程度，并改善其神经行为和记忆能力。此外，miR-21的过表达在体内和体外下调CCL3以抑制IKKα/β和p65磷酸化，从而破坏NF-κB信号通路。综上所述，本研究的关键发现在于miR-21通过抑制CCL3对新生大鼠的HIBD的脑保护作用。通过获得和丧失功能的实验检查了神经元凋亡及其对NF-κB信号通路相关因子的影响。获得的数据表明，miR-21的上调可通过下调CCL3来显着降低HIBD大鼠的脑梗死体积和脑组织损伤程度，并改善其神经行为和记忆能力。此外，miR-21的过表达在体内和体外下调CCL3以抑制IKKα/β和p65磷酸化，从而破坏NF-κB信号通路。综上所述，本研究的关键发现在于miR-21通过抑制CCL3对新生大鼠的HIBD的脑保护作用。通过获得和丧失功能的实验检查了神经元凋亡及其对NF-κB信号通路相关因子的影响。获得的数据表明，miR-21的上调可通过下调CCL3来显着降低HIBD大鼠的脑梗死体积和脑组织损伤程度，并改善其神经行为和记忆能力。此外，miR-21的过表达在体内和体外下调CCL3以抑制IKKα/β和p65磷酸化，从而破坏NF-κB信号通路。综上所述，本研究的关键发现在于miR-21通过抑制CCL3对新生大鼠的HIBD的脑保护作用。获得的数据表明，miR-21的上调可通过下调CCL3来显着降低HIBD大鼠的脑梗死体积和脑组织损伤程度，并改善其神经行为和记忆能力。此外，miR-21的过表达在体内和体外下调CCL3以抑制IKKα/β和p65磷酸化，从而破坏NF-κB信号通路。综上所述，本研究的关键发现在于miR-21通过抑制CCL3对新生大鼠的HIBD的脑保护作用。获得的数据表明，miR-21的上调可通过下调CCL3来显着降低HIBD大鼠的脑梗死体积和脑组织损伤程度，并改善其神经行为和记忆能力。此外，miR-21的过表达在体内和体外下调CCL3以抑制IKKα/β和p65磷酸化，从而破坏NF-κB信号通路。综上所述，本研究的关键发现在于miR-21通过抑制CCL3对新生大鼠的HIBD的脑保护作用。miR-21的过表达下调CCL3在体内和体外均抑制IKKα/β和p65磷酸化，从而破坏NF-κB信号通路。综上所述，本研究的关键发现在于miR-21通过抑制CCL3对新生大鼠的HIBD的脑保护作用。miR-21的过表达下调CCL3在体内和体外均抑制IKKα/β和p65磷酸化，从而破坏NF-κB信号通路。综上所述，本研究的关键发现在于miR-21通过抑制CCL3对新生大鼠的HIBD的脑保护作用。