Analysis of role of rat cerebral pericytes in cerebral vasospasm after subarachnoid hemorrhage and molecular mechanism of neurovascular injury

TIMP-3 Alleviates White Matter Injury After Subarachnoid Hemorrhage in Mice by Promoting Oligodendrocyte Precursor Cell Maturation

Subarachnoid hemorrhage (SAH) is associated with high mortality and disability rates, and secondary white matter injury is an important cause of poor prognosis. However, whether brain capillary pericytes can directly affect the differentiation and maturation of oligodendrocyte precursor cells (OPCs) and subsequently affect white matter injury repair has still been revealed. This study was designed to investigate the effect of tissue inhibitor of metalloproteinase-3 (TIMP-3) for OPC differentiation and maturation. PDGFRβret/ret and wild-type C57B6J male mice were used to construct a mouse model of SAH via endovascular perforation in this study. Mice were also treated with vehicle, TIMP-3 RNAi or TIMP-3 RNAi + TIMP-3 after SAH. The effect of TIMP-3 on the differentiation and maturation of OPCs was determined using behavioral score, ELISA, transmission electron microscopy, immunofluorescence staining and cell culture. We found that TIMP-3 was secreted mainly by pericytes and that SAH and TIMP-3 RNAi caused a significant decrease in the TIMP-3 content, reaching a nadir at 24 h, followed by gradual recovery. In vitro, the myelin basic protein content of oligodendrocytes after oxyhemoglobin treatment was increased by TIMP-3 overexpression. The data indicates TIMP-3 could promote the differentiation and maturation of OPCs and subsequently improve neurological outcomes after SAH. Therefore, TIMP-3 could be beneficial for repair after white matter injury and could be a potential therapeutic target in SAH.

Action mechanism of early cerebral injuries after spontaneous subarachnoid hemorrhage by silence Ghrelin and angiogenic factor with G-patch and FHA domain 1

The objective of the research was to investigate action mechanism of oxidative stress and cerebral injuries after subarachnoid hemorrhage (SAH) by Ghrelin and angiogenic factor G-patch and FHA domain 1 (Aggf1) and offer new research ideas to SAH clinical treatment and SAH-induced early cerebral injuries. SAH rat models were prepared by prechiasmatic anterior cistern injection. Specific Ghrelin and Aggf1 small interfering ribonucleic acid (siRNA) were designed and injected into silence Ghrelin or Aggf1 in rat left lateral ventricles. Rats were divided randomly into sham-operated (sham), SAH model, negative control siRNA, Ghrelin silence (Ghrelin^(-/-)), and Aggf1 silence groups. Changes of rat neurological impairment, encephaledema, cerebral tissue phosphorylated protein kinase (p-Akt), and content changes of caspase-3 protein and oxidative stress indexes were observed, including glutathione (GSH) and oxidized glutathione (GSSG). Results showed scores of neurological impairment and water content in SAH model group were reduced compared with sham group, while p-Akt protein and GSH contents were enhanced. However, caspase-3 protein and GSSG contents were declined, showing statistically meaningful difference (P < 0.05). Compared with SAH model group, scores of neurological impairment, cerebral tissue water content, and caspase-3 protein and GSSG contents in silence Ghrelin and Aggf1 groups were increased, while p-Akt protein and GSH contents were decreased, demonstrating statistically meaningful difference (P < 0.05). To conclude, silence Ghrelin and Aggf1 aggravated early cerebral injuries after SAH, revealing that Ghrelin and Aggf1 could protect brains to some degree.

Baicalin suppresses autophagy-dependent ferroptosis in early brain injury after subarachnoid hemorrhage

Early brain injury, characterized by massive cell apoptosis or death, is identified as a critical pathophysiological process during subarachnoid hemorrhage (SAH). Ferroptosis, a class of autophagy-dependent cell death discovered in 2012, is induced by iron-dependent lipid peroxidation accumulation. The present study was designed to study the role of baicalin in autophagy-dependent ferroptosis in early brain injury after SAH. Neurological scores and brain water content were measured to evaluate brain injury. Measurement of iron ion, malondialdehyde (MDA), lipid reactive oxygen species was conducted for ferroptosis evaluation. Immunofluorescence staining, western blotting, and flow cytometry analysis were used to evaluate autophagy and apoptosis. First, we observed that, compared with sham rats, SAH rats had lower neurobehavioral scores. Next, baicalin was proven to decrease the Fe²⁺, malondialdehyde, and ROS levels in the brain tissues of rats. Also, baicalin was confirmed to suppress the beclin1, LC3-II, and LC3-I protein levels in rat brain tissues. Moreover, we found that baicalin inhibited neuronal apoptosis. Finally, the effects of baicalin on brain injury in the SAH rats were verified. Overall, our results demonstrated that baicalin suppressed autophagy-dependent ferroptosis in EBI after SAH.