Objective To investigate the expression of targeted regulation of microRNA-146a (miR-146a) on E-box zinc finger protein 1 gene (ZEB1) and its related molecular mechanisms involved in neuroprotection and autophagy inhibition in a rat model of cerebral hemorrhage.
Methods Forty 8-week-old male SD rats were randomly divided into four groups: sham operation group, model group, miR-146a overexpression group and miR-146a underexpression group, with 10 rats in each group. Except for the sham operation group, the other three groups were induced to establish an aneurysmal spontaneous intracerebral hemorrhage rat model using type VII collagenase. Rats of four groups were fed a high-salt diet for 6 weeks and euthanized after an additional feeding for 20 weeks. Neurological function modified neurologic severity score (mNSS) and brain water content were compared among the four groups. FJC staining was used to detect the number of degenerated neurons; TUNEL staining was used to detect apoptosis; hematoxylin-eosin (HE) staining was used to observe pathological changes in brain tissue; quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression of miR-146a and ZEB1 mRNA; Western blot was used to detect the expression of ZEB1, autophagy-related proteins human recombinant autophagy effector protein (Beclin 1) and microtubule-associated protein 1 light chain 3 (LC3).
Results Compared to the sham surgery group, the model group showed a significant increase in mNSS score, brain water content, the number of degenerated neurons and cell apoptosis rate, and the expression level of miR-146a was significantly decreased, while the expressions of ZEB1 mRNA, as well as ZEB1, Beclin 1and LC3 proteins, were significantly increased in the model group (P < 0.05). Compared to the model group, the miR-146a overexpression group exhibited a significant decrease in mNSS score, brain water content, the number of degenerated neurons and cell apoptosis rate, and the expression level of miR-146a was significantly increased, while the expressions of ZEB1 mRNA, as well as ZEB1, Beclin 1 and LC3 proteins were significantly reduced in the miR-146a overexpression group (P < 0.05). Compared to the model group, the miR-146a low-expression group showed a further increase in mNSS score, brain water content, the number of degenerated neurons and cell apoptosis rate, and the expression level of miR-146a was further decreased, while the expressions of ZEB1 mRNA, as well as ZEB1, Beclin 1 and LC3 proteins were further elevated in the miR-146a low-expression group (P < 0.05).
Conclusion Upregulating miR-146a can exert neuroprotective effects by targeting and inhibiting ZEB1 gene and protein expression, as well as regulating autophagy activity.
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