Overexpression of miR-210 Attenuates Inflammatory Reaction in Mice with Cerebral Infarction by Inhibiting HIF-1α/iNOS Pathway

Abstract

Purpose: This study aimed to verify the targeted inhibition effect of microRNA (miR)-210 on hypoxia inducible factor 1α (HIF-1α), and to explore the mechanism of HIF-1α/inducible nitric oxide synthase (iNOS) pathway in the inflammatory reaction after cerebral infarction. Methods: The mouse models of cerebral ischemia infarction and drug intervention were constructed, and the mice were grouped into the cerebral infarction + miR-210 antagomir group, cerebral infarction group, sham group, cerebral infarction + miR-210 agomir group, and cerebral infarction + 2-methoxyestradiol (2ME2) (HIF-1α inhibitor) group. The neurological functions were determined by water maze test and neurological impairment score, the percentage of cerebral infarction area was determined by triphenyltetrazolium chloride (TTC), and the levels of inflammatory factors (Tumour Necrosis Factor alpha (TNF-α) and interleukin 6 (IL-6)) in the serum of mice in each group were determined by the automatic biochemical analyzer. The oxygen-glucose deprivation/reoxygenation (OGD/R) model of brain neurons in mice was constructed, and the mice were grouped into OGD/R + miR-210 knockdown group, OGD/R group, normal group, and OGD/R + miR-210 over-expression group, and OGD/R + 2ME2 (HIF-1α inhibitor) group. Results: The water maze test and neurological impairment score showed that neurological abnormalities were observed in mice after cerebral infarction but were improved after over-expressing miR-210. The test results of TTC and the levels of TNF-α and IL-6 showed the inflammation in mice after cerebral infarction, which was alleviated after over-expressing miR-qu210 (the levels of IL-6 and TNF-α). The results of correlation analysis showed that the percentage of cerebral infarction area, the degree of neurological injury and the expressions of HIF-1α and iNOS in brain tissues were positively correlated with the degree of inflammatory injury, and miR-210 expression in brain tissues was negatively correlated with the degree of inflammatory injury. The results of luciferase reporter assay showed that miR-210 could target the regulation of HIF-1α. The results of real-time reverse transcription-polymerase chain reaction (qRT-PCR) showed that the expression of miR-210 was down-regulated after cerebral infarction. The results of Western blot showed that the expressions of HIF-1α and iNOS were up-regulated after cerebral infarction, and the overexpression of miR-210 could inhibit the expressions of HIF-1α and iNOS. Conclusions: The overexpression of miR-210 can weaken the inflammatory reaction of cerebral infarction in mice by inhibiting the HIF-1α/iNOS pathway and then improve the neural functions of mice.