Histochemistry of microinfarcts in the mouse brain after injection of fluorescent microspheres into the common carotid artery

Assessment of Inner Blood-Retinal Barrier: Animal Models and Methods

Proper functioning of the neural retina relies on the unique retinal environment regulated by the blood-retinal barrier (BRB), which restricts the passage of solutes, fluids, and toxic substances. BRB impairment occurs in many retinal vascular diseases and the breakdown of BRB significantly contributes to disease pathology. Understanding the different molecular constituents and signaling pathways involved in BRB development and maintenance is therefore crucial in developing treatment modalities. This review summarizes the major molecular signaling pathways involved in inner BRB (iBRB) formation and maintenance, and representative animal models of eye diseases with retinal vascular leakage. Studies on Wnt/β-catenin signaling are highlighted, which is critical for retinal and brain vascular angiogenesis and barriergenesis. Moreover, multiple in vivo and in vitro methods for the detection and analysis of vascular leakage are described, along with their advantages and limitations. These pre-clinical animal models and methods for assessing iBRB provide valuable experimental tools in delineating the molecular mechanisms of retinal vascular diseases and evaluating therapeutic drugs.

Neuroprotective effect of Astragali Radix on cerebral infarction based on proteomics

Objective: Astragali Radix (AR, Huangqi in Chinese) has a neuroprotective effect on cerebral infarction (CI). In order to explore the biological basis and therapeutic mechanism of AR in CI, a double-blind randomized controlled trial was established in this study, and proteomics analysis was carried out on serum samples of patients. Methods: The patients were divided into the AR group (n = 35) and the control group (n = 30). The curative effect was evaluated by the traditional Chinese medicine (TCM) syndrome score and clinical indicators, and the serum of the two groups was analyzed by proteomics. Based on bioinformatics analysis methods, the changes in differential proteins between two groups of samples were explored, and the key proteins were validated through enzyme-linked immunosorbent assay (ELISA). Results: The results of this study showed that the scores of deficiency of vital energy (DVE), blood stasis (BS), and NIH Stroke Scale (NIHSS) decreased significantly (p < 0.05), while the scores of the Barthel Index (BI) increased, indicating that AR could significantly improve the symptoms of CI patients. In addition, we found that compared with the control group, AR upregulated 43 proteins and downregulated 20 proteins, especially focusing on anti-atherosclerosis and neuroprotective effects. Moreover, ELISA indicated the levels of IL-6, TNF-α, VCAM-1, MCP-1, and ICAM-1 were significantly decreased in the serum of the AR group (p < 0.05, p < 0.01). Conclusion: This study found that AR can significantly recover the clinical symptoms of CI. Serum proteomics research results show that AR may act on IL-6, TNF-α, VCAM-1, MCP-1, and ICAM-1, and play anti-atherosclerosis and neuroprotective roles. Clinical Trial Registration: [clinicaltrials.gov], identifier [NCT02846207].

To explore the regulatory effect of Buyang Huanwu Decoction on cerebral infarction based on quantitative proteomics

Buyang Huanwu Decoction (BYHW) contains chemical components such as ligustrazine, oxypaeoniflora, chlorogenic acid, and others. To explore the neuroprotective effect and potential target protein of BYHW in cerebral infarction (CI). A double-blind, randomized controlled trial was established and patients with CI were divided into the BYHW group (n = 35) and the control group (n = 30). To evaluate the efficacy by TCM syndrome score and clinical indicators, and to explore the changes of serum proteins by proteomics technology, so as to explore the mechanism of BYHW and potential target proteins. The study found that compared with the control group, the TCM syndrome score, including Deficiency of Vital Energy (DVE), Blood Stasis (BS), and NIHSS in the BYHW group decreased significantly (p < 0.05), and the Barthel Index (BI) score was significantly higher. A total of 99 differential regulatory proteins were identified by proteomics, which act on lipids and atherosclerosis, complement and coagulation cascade, and TNF-α signaling pathway. In addition, Elisa verified the results of proteomics and found that BYHW can reduce the neurological impairments focus on IL-1β, IL-6, TNF-α, MCP-1, MMP-9, and PAI-1. Significance: In this study, quantitative proteomics was used in combination with liquid chromatography-mass spectrometry (LC-MS/MS) to study the therapeutic effect of BYHW on cerebral infarction (CI) and potential changes in serum proteomics. In addition, the public proteomics database was used for bioinformatics analysis, and Elisa experiment verified the results of proteomics, further clarifying the potential protection mechanism of BYHW on CI.

The immunolocalization of cluster of differentiation 31, phalloidin and alpha smooth muscle actin on vascular network of normal and ischemic rat brain

Cluster of differentiation 31 (CD31), phalloidin and alpha smooth muscle actin (α-SMA) have been widely applied to label the cerebral blood vessels in the past years. Although CD31 is mainly used as endothelial marker in determining the cerebral capillaries, it seems likely that its labeling efficiency is closely correlated with the antibodies from the polyclonal or monoclonal one, as well as the conditions of blood vessels. In order to test this phenomenon, we compared the labeling characteristics of goat polyclonal anti-CD31 (gP-CD31) and mouse monoclonal anti-CD31 (mM-CD31) with those of phalloidin and α-SMA on the rat brain in health and ischemia/reperfusion (I/R) with the middle cerebral artery occlusion. By multiple immunofluorescence staining, it was found that gP-CD31 labeling expressed extensively on the cerebral capillaries forming the vascular networks on the normal and ischemic regions, but mM-CD31 labeling mainly presented on the capillaries in the ischemic region. In contrast to the vascular labeling with gP-CD31, phalloidin and α-SMA were mainly expressed on the wall of cortical penetrating arteries, and less on that of capillaries. By three-dimensional reconstruction analysis, it was clearly shown that gP-CD31 labeling was mainly located on the lumen side of vascular wall and was surrounded by phalloidin labeling and α-SMA labeling. These results indicate that gP-CD31 is more sensitive than mM-CD31 for labeling the cerebral vasculature, and is highly compatible with phalloidin and α-SMA for evaluating the cerebral vascular networks under the physiological and pathological conditions.

Temporal alteration of microglia to microinfarcts in rat brain induced by the vascular occlusion with fluorescent microspheres

Microglia, the resident immune cells in the central nervous system, can monitor the microenvironment and actively respond to ischemic stroke and other brain injuries. In this procedure, microglia and neurons can cross-talk via transmembrane chemokine, Fractalkine (CX3CL1), to impact one another. We used a rat model of multifocal microinfarcts induced by the injection of fluorescent microspheres into the right common carotid artery and examined the morphological alteration of blood vessels, microglia, astrocytes, and neurons at 6 h, 1, 7, and 14 days after modeling, along with neurobehavioral tests and the staining of CX3CL1 in this study. Our results demonstrated that in the infarcted regions, astrocytes and microglia activated in response to neuronal degeneration and upregulation of cleaved caspase-3, which occurred concurrently with vascular alteration and higher expression of CX3CL1. We provided sequential histological data to shed light on the morphological changes after modeling, which would help in the identification of new targets and the choice of the ideal time window for therapeutic intervention in ischemic stroke.

New Drug Delivery Systems Developed for Brain Targeting

The blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (B_CSF) are two of the most complex and sophisticated concierges that defend the central nervous system (CNS) by numerous mechanisms. While they maintain the neuro-ecological homeostasis through the regulated entry of essential biomolecules, their conservative nature challenges the entry of most of the drugs intended for CNS delivery. Targeted delivery challenges for a diverse spectrum of therapeutic agents/drugs (non-small molecules, small molecules, gene-based therapeutics, protein and peptides, antibodies) are diverse and demand specialized delivery and disease-targeting strategies. This review aims to capture the trends that have shaped the current brain targeting research scenario. This review discusses the physiological, neuropharmacological, and etiological factors that participate in the transportation of various drug delivery cargoes across the BBB/B_CSF and influence their therapeutic intracranial concentrations. Recent research works spanning various invasive, minimally invasive, and non-invasive brain- targeting approaches are discussed. While the pre-clinical outcomes from many of these approaches seem promising, further research is warranted to overcome the translational glitches that prevent their clinical use. Non-invasive approaches like intranasal administration, P-glycoprotein (P-gp) inhibition, pro-drugs, and carrier/targeted nanocarrier-aided delivery systems (alone or often in combination) hold positive clinical prospects for brain targeting if explored further in the right direction.