Synergic Effect of Borneol and Ligustrazine on the Neuroprotection in Global Cerebral Ischemia/Reperfusion Injury: A Region-Specificity Study

(+)-Borneol Protects Dopaminergic Neuronal Loss in Methyl-4-phenyl-1,2,3,6-tetrahydropyridine-Induced Parkinson's Disease Mice: A Study of Dopamine Level using In Vivo Brain Microdialysis

Considerable research efforts have been directed toward the symptom relief of Parkinson's disease (PD) by attenuating dopamine (DA) depletion. One common feature of these existing therapies is their unavailability of preventing the neurodegenerative process of dopaminergic neurons. (+)-Borneol, a natural highly lipid-soluble bicyclic monoterpene, has been reported to regulate the levels of monoamine neurotransmitters in the central nervous system and exhibit neuroprotective effects. However, the effect of (+)-borneol on the dopaminergic neuronal loss of methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mice is not defined. Herein, we first report that 30 mg/kg (+)-borneol significantly attenuated the motor deficits of PD mice, which benefits from markedly increasing the level of DA and decreasing the metabolic rate of DA in the striatum of conscious and freely moving mouse detected by ultraperformance liquid chromatography tandem mass spectrometry online combined with in vivo brain microdialysis sampling. It is worth noting that the enhanced level of DA by (+)-borneol was enabled by the reduction in loss of tyrosine hydroxylase-immunoreactive dopaminergic neurons in the substantia nigra and striatum and promotion of reserpine- or nomifensine-induced DA release in PD mice. Interestingly, (+)-borneol evidently inhibited the decreased expression levels of DA transporter (DAT) and vesicular monoamine transporter 2 (VMAT2) on the MPTP mouse model of PD. Moreover, (+)-borneol suppressed the neuroinflammation by inhibiting the production of IL-1β, IL-6, and TNF-α and attenuated oxidative stress by decreasing the level of MDA and increasing the activities of SOD and GSH-px in PD mice. These findings demonstrate that (+)-borneol protects DA neurons by inhibiting neuroinflammation and oxidative stress. Further research work for the neuroprotection mechanism of (+)-borneol will focus on reactive oxygen species-mediated apoptosis. Therefore, (+)-borneol is a potential therapeutic candidate for retarding the neurodegenerative process of PD.

Combined Catalpol and Tetramethylpyrazine Promote Axonal Plasticity in Alzheimer's Disease by Inducing Astrocytes to Secrete Exosomes Carrying CDK5 mRNA and Regulating STAT3 Phosphorylation

Alzheimer's disease (AD) is a common progressive degenerative disease of the central nervous system in aging populations. This study aimed to investigate the effects of combined catalpol and tetramethylpyrazine (CT) in promoting axonal plasticity in AD and the potential underlying mechanism. Astrocytes were treated with different concentrations of compatible CT. Exosomes were collected and subjected to sequencing analysis, which was followed by the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of differentially expressed genes. Amyloid precursor protein/presenilin 1 (APP/PS1) double-transfected male mice were used as the in vivo AD models. Astrocyte-derived exosomes that were transfected with cyclin-dependent kinase 5 (CDK5) or CT treatment were injected into the tail vein of mice. The levels of CDK5, synaptic plasticity marker protein neurofilament 200 (NF200), and growth-associated protein 43 (GAP-43) in the hippocampus of mice were compared in each group. Immunofluorescence staining was used to detect the localization of STAT3 and to visualize synaptic morphology via β-tubulin-III (TUBB3). Astrocyte-derived exosomes transfected with siCDK5 or treated with CT were co-cultured with HT-22 cells, which were untransfected or silenced for signal transducer and activator of transcription 3 (STAT3). Amyloid β-protein (Aβ)1-42 was induced in the in vitro AD models. The viability, apoptosis, and expression levels of NF200 and GAP-43 proteins in the hippocampal neurons of each group were compared. In total, 166 differentially expressed genes in CT-induced astrocyte-derived exosomes were included in the KEGG analysis, and they were found to be enriched in 12 pathways, mainly in axon guidance. CT treatment significantly increased the level of CDK5 mRNA in astrocyte-derived exosomes-these exosomes restored CDK5 mRNA and protein levels in the hippocampus of the in vivo AD model mice and the in vitro AD model; promoted p-STAT3 (Ser727), NF200 and GAP-43 proteins; and promoted the regeneration and extension of neuronal synapses. Silencing of CDK5 blocked both neuronal protection as well as induction of axonal plasticity in AD by CT-treated exosomes in vitro and in vivo. Moreover, silencing of STAT3 blocked both neuronal protection as well as induction of axonal plasticity in AD caused by CDK5 overexpression or CT-treated astrocyte-induced exosomes. CT promotes axonal plasticity in AD by inducing astrocytes to secrete exosomes carrying CDK5 mRNA and regulating STAT3 (Ser727) phosphorylation.

Phytochemicals with protective effects against acute pancreatitis: a review of recent literature

CONTEXT

Acute pancreatitis (AP) is an acute abdominal inflammatory disease with episodes ranging from mild to fulminant symptoms which could include necrosis, systemic inflammation and multiple organ dysfunction. Increasing experimental evidence demonstrates that specific bioactive ingredients from natural plants have a favourable therapeutic effect on AP.

OBJECTIVE

The objective of this review is to summarize the protective effects and potential mechanisms of action of phytochemicals on the attenuation of AP.

METHODS

Experimental studies in vivo or in vitro between January 2016 and June 2021 were sought in PubMed and Web of Science using the following search terms: ('phytochemicals' OR 'medicinal plant' OR 'traditional medicine') AND ('pancreatitis' OR 'pancreatic damage' OR 'pancreatic injury'). Data concerning the basic characteristics of phytochemicals, therapeutic dose and potential molecular mechanisms related to AP were extracted in this study.

RESULTS

A total of 30 phytochemicals with potential therapeutic effects were reviewed and summarized systematically. According to their molecular pathways in AP, the underlying mechanisms of the phytochemicals were illustrated in detail.

DISCUSSION AND CONCLUSIONS

The phytochemicals with anti-inflammatory and antioxidant abilities may be efficient candidate drugs for AP treatment. Importantly, more preclinical investigations are needed to illustrate the efficacy of future phytochemicals.

(+)-Borneol inhibits the generation of reactive oxygen species and neutrophil extracellular traps induced by phorbol-12-myristate-13-acetate

Background and purpose: Neutrophil extracellular traps (NETs) are special web-like structures that can be generated in both infectious and noninfectious diseases. Previous studies showed that reactive oxygen species (ROS) were crucial in the formation of NETs (NETosis). The purpose of this study is to evaluate the effect of (+)-borneol, an antioxidant, on NETosis.

Methods: Human neutrophils were stimulated with phorbol-12-myristate-13-acetate (PMA) to induce NETosis in vitro. Neutrophils treated with (+)-borneol at three different time points (−30 min, 0, and 30 min) associated with PMA stimulation were used to examine the effect of (+)-borneol on the formation of NETs. The ROS generation of neutrophils was also measured to explore the potential mechanism of the inhibitory effect of (+)-borneol on NETosis.

Results: (+)-Borneol pretreatment inhibited NETosis induced by PMA. Immunofluorescence staining visualized and confirmed the inhibitory effect. (+)-Borneol inhibited the burst of ROS in neutrophils caused by PMA. Suppressing NADPH oxidase or protein kinase C (PKC) eliminated the effect of (+)-borneol on NETosis. Moreover, inhibiting Toll-like receptor 2 (TLR2) led to increased NETosis which can be inhibited by (+)-borneol.

Conclusion: (+)-Borneol decreases the ROS level in activated neutrophils and inhibits NETosis triggered by PMA stimulation in vitro. (+)-Borneol therapy may be effective in some NET-dependent conditions.

Tetramethylpyrazine Protects Endothelial Injury and Antithrombosis via Antioxidant and Antiapoptosis in HUVECs and Zebrafish

Chuanxiong Rhizoma, the dried rhizome of Ligusticum chuanxiong Hort., is a commonly used drug for promoting blood circulation and dissipating congestion. Tetramethylpyrazine (TMP), the main active ingredient of Ligusticum chuanxiong, has significant antioxidant, anti-inflammatory, and vascular protective effects. However, the protective properties and underlying mechanisms of TMP against endothelial injury-induced insufficient angiogenesis and thrombosis have not been elucidated. Therefore, we aimed to explore the protective effects of TMP on endothelial injury and its antithrombotic effects and study the mechanism. In vitro experiments showed that TMP could alleviate hydrogen peroxide– (H₂O₂–) induced endothelial injury of human umbilical vein endothelial cells (HUVECs) and the protective mechanism might be related to the regulation of MAPK signaling pathway, and its antioxidative and antiapoptotic effects. In vivo experiments showed that TMP restored PTK787-induced damage to intersegmental vessels (ISVs) in Tg(fli-1: EGFP)y1 transgenic (Flik) zebrafish larvae. Similarly, adrenalin hydrochloride– (AH–) induced reactive oxygen species (ROS) production and thrombosis in AB strain zebrafish were inhibited by TMP. RT-qPCR assay proved that TMP could inhibit the expression of fga, fgb, fgg, f7, and von Willebrand factor (vWF) mRNA to exert an antithrombotic effect. Our findings suggest that TMP can contribute to endothelial injury protection and antithrombosis by modulating MAPK signaling and attenuating oxidative stress and antiapoptosis.

Multiple regulation and targeting effects of borneol in the neurovascular unit in neurodegenerative diseases

Efficient delivery of brain-targeted drugs is highly important for the success of therapies in neurodegenerative diseases. Borneol has several biological activities, such as anti-inflammatory and cell penetration enhancing effect, and can regulate processes in the neurovascular unit (NVU), such as protein toxic stress, autophagosome/lysosomal system, oxidative stress, programmed cell death and neuroinflammation. However, the influence of borneol on NVU in neurodegenerative diseases has not been fully explained. This study searched the keywords 'borneol', 'neurovascular unit', 'endothelial cell', 'astrocyte', 'neuron', 'blood-brain barrier', 'neurodegenerative diseases' and 'brain disease', in PubMed, BioMed Central, China National Knowledge Infrastructure (CNKI), and Bing search engines to explore the influence of borneol on NVU. In addition to the principle and mechanism of penetration of borneol in the brain, this study also showed its multiple regulation effects on NVU. Borneol was able to penetrate the blood-brain barrier (BBB), affecting the signal transmission between BBB and the microenvironment of the brain, down-regulating the expression of inflammatory and oxidative stress proteins in NVU, especially in microglia and astrocytes. In summary, borneol is a potential drug delivery agent for drugs against neurodegenerative diseases.

Progress in Borneol Intervention for Ischemic Stroke: A Systematic Review

Background: Borneol is a terpene and bicyclic organic compound that can be extracted from plants or chemically synthesized. As an important component of proprietary Chinese medicine for the treatment of stroke, its neuroprotective effects have been confirmed in many experiments. Unfortunately, there is no systematic review of these studies. This study aimed to systematically examine the neuroprotective effects of borneol in the cascade reaction of experimental ischemic stroke at different periods. Methods: Articles on animal experiments and cell-based research on the actions of borneol against ischemic stroke in the past 20°years were collected from Google Scholar, Web of Science, PubMed, ScienceDirect, China National Knowledge Infrastructure (CNKI), and other biomedical databases. Meta-analysis was performed on key indicators in vivo experiments. After sorting the articles, we focused on the neuroprotective effects and mechanism of action of borneol at different stages of cerebral ischemia. Results: Borneol is effective in the prevention and treatment of nerve injury in ischemic stroke. Its mechanisms of action include improvement of cerebral blood flow, inhibition of neuronal excitotoxicity, blocking of Ca²⁺ overload, and resistance to reactive oxygen species injury in the acute ischemic stage. In the subacute ischemic stage, borneol may antagonize blood-brain barrier injury, intervene in inflammatory reactions, and prevent neuron excessive death. In the late stage, borneol promotes neurogenesis and angiogenesis in the treatment of ischemic stroke. Conclusion: Borneol prevents neuronal injury after cerebral ischemia via multiple action mechanisms, and it can mobilize endogenous nutritional factors to hasten repair and regeneration of brain tissue. Because the neuroprotective effects of borneol are mediated by various therapeutic factors, deficiency caused by a single-target drug is avoided. Besides, borneol promotes other drugs to pass through the blood-brain barrier to exert synergistic therapeutic effects.

Neuroprotective Effect for Cerebral Ischemia by Natural Products: A Review

Natural products have a significant role in the prevention of disease and boosting of health in humans and animals. Stroke is a disease with high prevalence and incidence, the pathogenesis is a complex cascade reaction. In recent years, it’s reported that a vast number of natural products have demonstrated beneficial effects on stroke worldwide. Natural products have been discovered to modulate activities with multiple targets and signaling pathways to exert neuroprotection via direct or indirect effects on enzymes, such as kinases, regulatory receptors, and proteins. This review provides a comprehensive summary of the established pharmacological effects and multiple target mechanisms of natural products for cerebral ischemic injury in vitro and in vivo preclinical models, and their potential neuro-therapeutic applications. In addition, the biological activity of natural products is closely related to their structure, and the structure-activity relationship of most natural products in neuroprotection is lacking, which should be further explored in future. Overall, we stress on natural products for their role in neuroprotection, and this wide band of pharmacological or biological activities has made them suitable candidates for the treatment of stroke.

Borneol in cardio-cerebrovascular diseases: Pharmacological actions, mechanisms, and therapeutics

With the coming acceleration of global population aging, the incidence rate of cardio-cerebrovascular diseases (CVDs) is increasing. It has become the leading cause of human mortality. As a natural drug, borneol (BO) not only has anti-inflammatory, anti-oxidant, anti-apoptotic, anti-coagulant activities and improves energy metabolism but can also promote drugs to enter the target organs or tissues through various physiological barriers, such as the blood-brain barrier (BBB), mucous membrane, skin. Thus, it has a significant therapeutic effect on various CVDs, which has been confirmed in a large number of studies. However, the pharmacological actions and mechanisms of BO on CVDs have not been fully investigated. Hence, this review summarizes the pharmacological actions and possible mechanisms of BO, which provides novel ideas for the treatment of CVDs.

Borneol protects against cerulein-induced oxidative stress and inflammation in acute pancreatitis mice model

Borneol is a commonly used flavouring substance in traditional Chinese medicine, which possesses several pharmacological activities including analgesic, antiinflammatory, and antioxidant properties. The aim of this study was to investigate the effects of borneol on cerulein-induced acute pancreatitis (AP) model. Swiss albino mice were pretreated with borneol (100 and 300 mg/kg) daily for 7 days, before six consecutive injections of cerulein (50 μg/kg/hr, intraperitoneally). The protective effect of borneol was studied by biochemical, enzyme linked immunosorbent assay, histological, immunoblotting, and immunohistochemical analysis. Oral administration of borneol significantly attenuated pancreatic damage by reducing amylase, lipase levels and histological changes. Borneol attenuated cerulein-induced oxidative-nitrosative stress by decreasing malondialdehyde, nitrite levels, and elevating reduced glutathione levels. Pancreatic inflammation was ameliorated by inhibiting myeloperoxidase activity and pro-inflammatory cytokine (Interleukins and TNF-α) levels. Furthermore, borneol administration significantly increased nuclear factor E2-related factor 2 (Nrf2), superoxide dismutase (SOD1) expression and reduced phospho-NF-κB p65 expression. Treatment with borneol significantly inhibited TNF-α, IL-1β, IL-6, and inducible nitric oxide synthase expression in cerulein-induced AP mouse model. Together, these results indicate that borneol which is currently used as US-FDA approved food adjuvant has the potential to attenuate cerulein-induced AP possibly by reducing the oxidative damage and pancreatic inflammation by modulating Nrf2/NF-κB pathway.

Preparation, Characterization and in vivo Study of Borneol-Baicalin-Liposomes for Treatment of Cerebral Ischemia-Reperfusion Injury

Purpose

Baicalin (BA) has a good neuroprotective effect, but it is eliminated quickly in the body and does not easily reach the brain. In this experiment, borneol (BO) was used as an auxiliary drug to prepare borneol-baicalin-liposomes (BO-BA-LP) to prolong the efficacy time of BA, synergistically synergize, introduce drugs into the brain, and better exert the therapeutic effect on cerebral ischemia-reperfusion (I/R) injury.

Methods

Through single-factor inspection and response surface optimization analysis, obtained the best preparation process of BO-BA-LP and characterized by various analytical techniques. Validated the long-term effectiveness of BA-BO-LP through pharmacokinetic studies and conducted pharmacodynamic studies on the middle cerebral artery occlusion (MCAO) rat model to verify the therapeutic effect of BO-BA-LP on cerebral I/R injury.

Results

The optimum preparation conditions of BO-BA-LP were as follows: the dosage of BO was 9.55 mg, the ratio of phospholipid to drug was 4.02:1, the ratio of phospholipid to cholesterol was 7.25:1, the entrapment efficiency (EE) was 41.49%, and the drug loading (DL) was 4.29%. The particle size range of the liposomes was 167.1 nm, and the polydispersity index (PDI) range was 0.113. The results of pharmacokinetic experiments showed that the combination of BA and BO liposomes effectively improved the pharmacokinetic parameters of BA and prolonged the half-life of BA. Pharmacodynamic studies have found that, compared with BA-LP, BO-BA-LP can significantly improve neurological deficits, cerebral infarction volume, and brain pathological states on MCAO rats.

Conclusion

These results demonstrated that BO-BA-LP can improve the circulation of drugs in the blood, and the addition of BO can enhance the therapeutic effect of BA and effectively improve cerebral I/R.

Synergistic protection of tetramethylpyrazine phosphate and borneol on brain microvascular endothelium cells injured by hypoxia

The combination of tetramethylpyrazine phosphate (TMPP) and borneol (BO) protects against cerebral ischemia. However, the mechanism for their synergistic effect is unclear. In this study, an oxygen-glucose deprivation (OGD) injured brain model was induced in microvascular endothelium cells (BMECs). TMPP and BO concentrations were optimized according to an MTT assay. Cells were divided into five groups: control, model, TMPP, BO, and TMPP+BO. Subsequently, oxidative stress was evaluated based on the levels of superoxide dismutase (SOD), malondialdehyde (MDA), catalase (CAT), glutathione peroxidase (GSH-Px), and reactive oxygen species (ROS). Intracellular calcium ([Ca²⁺]i) was detected using a laser confocal microscope. Cellular apoptosis was examined via Hoechst 33342 staining, flow cytometry, and expression of p53, B-cell lymphoma 2 (BCL-2), BCL-2-like protein 4 (BAX), and caspase-3 mRNA. Angiogenesis was evaluated based on expression of basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), fibroblast growth factor receptor 1 (FGFR1), Vascular endothelial growth factor receptor 1 (VEGFR1), and VEGFR2. Results showed that 5.0 μM TMPP and 0.5 μM BO were optimal. Monotherapy significantly enhanced CAT, BCL-2, and VEGF, and also reduced [Ca²⁺]i, apoptosis, and BAX. TMPP increased SOD, GSH-Px, and bFGF, and reduced MDA, ROS, p53, and caspase-3 levels. BO reduced VEGFR1 expression. TMPP+BO combination exhibited synergistic effects in decreasing apoptosis, and modulating expression of BCL-2, BAX, and VEGFR1. These results indicate that protection of OGD-injured BMECs by TMPP+BO combination involves anti-oxidation, apoptosis inhibition, and angiogenesis. Moreover, their synergistic mechanism was mainly related to the regulation of apoptosis and angiogenesis.

The Ethanolic Extract of Caesalpinia sappan Heartwood Inhibits Cerebral Ischemia/Reperfusion Injury in a Rat Model Through a Multi-Targeted Pharmacological Mechanism

Background: Caesalpinia sappan L. (C. sappan) is a traditional Chinese medicinal plant. The dried heartwood of C. sappan (also known as Sappan wood) has been widely used for the folkloric medical treatment of ischemic cerebral stroke in China. However, the detailed underlying pharmacological mechanism still remains largely unexplored. Methods: In this study, a middle cerebral artery occlusion (MCAO) rat model was employed to elucidate the mechanism of the anti-cerebral ischemic effects of C. sappan ethanolic extract (CEE). Moreover, systemic multi-target identification coupled with gene ontology biological process (GO BP) and reactome pathway analysis was used to investigate the potential neuroprotective mechanism. Furthermore, the presumed mechanism was confirmed through biological analysis by determining the effects of CEE on the identified signaling pathways in PC12 cells model-induced by oxygen-glucose deprivation/reperfusion (OGD/R). Results: Our study demonstrates that CEE (both through in vivo administration at a dosage of 300 mg/kg and through in vitro incubation at a dosage of 2.4 μg/mL) is a neuroprotective agent that can effectively inhibit neuronal damage, promote synaptic generation, and suppress the activation of neutrophils, microglia, and astrocytes. Moreover, the neuroprotective mechanism of CEE is mediated via regulating 150 potential target proteins, which are associated with 6 biological processes and 10 pathways, including JAK-STAT, HSP90 and DNA damage/telomere stress. Conclusion: CEE can exert neuroprotective effect through multi-target pharmacological mechanisms to prevent ischemia/reperfusion-induced cerebral injury.

Zinc ions regulate opening of tight junction favouring efflux of macromolecules via the GSK3β/snail-mediated pathway

Zinc is an essential trace element presenting in particularly high concentration in the brain. In some regions, e.g. lateral amygdala, subiculum and hippocampus, rapidly-exchangeable zinc may transiently reach even up to 600 μM. To explore the possible roles of high-concentration Zn²⁺ in regulating the blood-brain barrier (BBB), we investigated the effects of Zn²⁺ on the functions and structures of the tight junction (TJ) with an in vitro model of a Madin-Darby canine kidney (MDCK) cell monolayer. The experimental results indicated that high concentrations (>200 μM) of Zn²⁺ can affect the TJ integrity in a polarized manner. Basolateral addition of Zn²⁺ led to reversible TJ opening with pore paths of r ∼ 2 nm or more depending on Zn²⁺ concentration. The efflux/influx ratios of different sized probes were found to be ∼4.6 for FD4 (M_W 4000) and ∼1.8 for Eu-DTPA (M_W 560), suggesting that the Zn²⁺-induced paracelluar channels favour efflux especially for macromolecules. Further mechanistic studies revealed that the elevated intracellular Zn²⁺ taken from the basolateral side can increase phosphorylation of glycogen synthase kinase (GSK) 3β, primarily due to the inhibition of calcineurin (CaN), thus resulting in the elevation of the snail transcriptional repressors. Subsequently, Zn²⁺ can cause the down-regulation of claudin-1, breakage of occludin and ZO-1 rings, and collapse of basolateral F-actin structures. These overall factors result in the formation of a trumpet-like paracellular channel, which allows asymmetric solute permeation. The ERK1/2 and JNK1/2 pathways may also be involved in the Zn²⁺-induced TJ opening process, while the activation of matrix metalloproteinase was not observed. Our results may suggest a potential role of zinc in regulation of BBB permeability associated with brain clearance of metabolites through the glymphatic system.

In vivo microdialysis with ultra performance liquid chromatography-mass spectrometry for analysis of tetramethylpyrazine and its interaction with borneol in rat brain and blood

Tetramethylpyrazine (TMP) has been widely used in the treatment of ischemic cerebrovascular disease. However, the mechanism of TMP and how to increase its bioavailability need to be further explored. In our study, an in vivo microdialysis sampling technique coupled with ultra-performance liquid chromatography-mass spectrometry method was developed to investigate the pharmacokinetic properties of TMP and its interaction with different doses of borneol (BO) in rats. Linearity of TMP in brain and blood dialysates exhibited good linear relationships over the concentration range of 0.991-555.14 ng/mL. The specificity, linearity, accuracy, precision, matrix effect and stability were within acceptable ranges. The results demonstrated that BO had a marked impact on the pharmacokinetic properties of TMP. After co-administration, the areas under the concentration-time curve (AUC) of TMP in brain and blood were significantly increased. Meanwhile, the peak concentration of TMP in brain was also enhanced. The AUC_Brain /AUC_Blood of TMP, increased from 44% to 56 and 60.8% after co-administration with BO (15 and 30 mg/kg). The pharmacodynamic results showed that TMP co-administration with BO enhanced the cerebral blood flow during the period of ischemia and reduced the infarct volume. Overall, it might be an effective way to treat stroke to use TMP co-administered with BO.

Anti-TNF-alpha antibody attenuates subarachnoid hemorrhage-induced apoptosis in the hypothalamus by inhibiting the activation of Erk

BACKGROUND

Subarachnoid hemorrhage (SAH) can induce apoptosis in many regions of the brain including the cortex and hippocampus. However, few studies have focused on apoptosis in the hypothalamus after SAH. Although some antiapoptotic strategies have been developed for SAH, such as anti-tumor necrosis factor-alpha (TNF-α) antibody, the molecular mechanisms underlying this condition have yet to be elucidated. Therefore, the purpose of this study was to evaluate whether SAH could induce apoptosis in the hypothalamus and identify the potential molecular mechanisms underlying the actions of anti-TNF-α antibody, as a therapeutic regimen, upon apoptosis.

MATERIALS AND METHODS

SAH was induced in a rat model. Thirty minutes prior to SAH, anti-TNF-α antibody or U0126, an extracellular signal-regulated kinase (Erk) inhibitor, was microinjected into the left lateral cerebral ventricle. In addition, phorbol-12-myristate-13-acetate was injected intraperitoneally immediately after the anti-TNF-α antibody microinjection. Then, real-time polymerase chain reaction, Western blotting and immunohistochemistry were used to detect the expression of caspase-3, bax, bcl-2, phosphorylated Erk (p-Erk) and Erk. Finally, anxiety-like behavior was identified by using open field.

RESULTS

Levels of caspase-3, bax and bcl-2, all showed a temporary rise after SAH in the hypothalamus, indicating the induction of apoptosis in this brain region. Interestingly, we found that the microinjection of anti-TNF-α antibody could selectively block the elevated levels of bax, suggesting the potential role of anti-TNF-α antibody in the inhibition of SAH-induced apoptosis in the hypothalamus. Moreover, we found that Erk activation was necessary for apoptosis after SAH and that the microinfusion of anti-TNF-α antibody could inhibit apoptosis by suppressing the increase of p-Erk in the hypothalamus. Finally, our data indicated that the infusion of anti-TNF-α antibody could improve anxiety-like behavior.

CONCLUSION

Collectively, our data demonstrate that anti-TNF-α antibody attenuates apoptosis in the hypothalamus by inhibiting the activation of Erk, which plays an important role in the treatment of SAH.

Tetramethylpyrazine phosphate and borneol combination therapy synergistically attenuated ischemia-reperfusion injury of the hypothalamus and striatum via regulation of apoptosis and autophagy in a rat model

The combination of tetramethylpyrazine (TMP) and borneol (BO) has shown promise for treatment of cerebral ischemia in clinical and experimental studies. However, the mechanism for the synergistic effect of these compounds is unclear. In this study, global cerebral ischemia-reperfusion (GCIR) was induced in rats that were subsequently treated with tetramethylpyrazine phosphate (TMPP) (13.3 mg/kg), BO (0.16 g/kg), or the combination TMPP + BO. Neuronal ultrastructure and intracellular calcium [Ca²⁺]i levels were evaluated in hypothalamus and striatum. Neuron autophagy was evaluated by expression of LC3 II/I, ULK1, Beclin1, BNIP3, mTOR, and pAMPK. Neuron apoptosis was examined via apoptosis index (AI) and expression of p53, Bcl-2, Bax, and caspase-3. Both monotherapies significantly improved neuronal ultrastructure, reduced numbers of apoptotic neurons and AI, attenuated [Ca²⁺]i overload, increased expression of pAMPK, ULK1, and LC3 II/I, and markedly reduced expression of mTOR, p53, and caspase-3 in hypothalamus and striatum. In hypothalamus, TMPP increased Bcl-2 expression and decreased Bax expression. In striatum, TMPP and BO increased Beclin1 expression while TMPP increased Bcl-2 expression and decreased Bax expression. TMPP + BO combination therapy enhanced expression of LC3 II/I, pAMPK, mTOR, and ULK1 in hypothalamus, and pAMPK, mTOR, ULK1, Beclin1, and Bax in striatum compared to the monotherapies. Combination therapy synergistically modulated p53 and adjusted Bcl-2 in striatum compared to TMPP and BO monotherapies, respectively. These results demonstrated a synergistic effect of TMPP + BO in protecting against hypothalamus and striatum in rats from ischemia-reperfusion injury and suggested that the mechanism involved shifting neurons from harmful apoptosis to protective autophagy and reducing neuronal [Ca²⁺]i.

Borneol, a novel agent that improves central nervous system drug delivery by enhancing blood-brain barrier permeability

The clinical application of central nervous system (CNS) drugs is limited by their poor bioavailability due to the blood-brain barrier (BBB). Borneol is a naturally occurring compound in a class of 'orifice-opening' agents often used for resuscitative purposes in traditional Chinese medicine. A growing body of evidence confirms that the 'orifice-opening' effect of borneol is principally derived from opening the BBB. Borneol is therefore believed to be an effective adjuvant that can improve drug delivery to the brain. The purpose of this paper is to provide a comprehensive review of information accumulated over the past two decades on borneol's chemical features, sources, toxic and kinetic profiles, enhancing effects on BBB permeability and their putative mechanisms, improvements in CNS drug delivery, and pharmaceutical forms. The BBB-opening effect of borneol is a reversible physiological process characterized by rapid and transient penetration of the BBB and highly specific brain regional distribution. Borneol also protects the structural integrity of the BBB against pathological damage. The enhancement of the BBB permeability is associated with the modulation of multiple ATP-binding cassette transporters, including P-glycoprotein; tight junction proteins; and predominant enhancement of vasodilatory neurotransmitters. Systemic co-administration with borneol improves drug delivery to the brain in a region-, dose- and time-dependent manner. Several pharmaceutical forms of borneol have been developed to improve the kinetic and toxic profiles of co-administered drugs and enhance their delivery to the brain. Borneol is a promising novel agent that deserves further development as a BBB permeation enhancer for CNS drug delivery.

PEG-b-(PELG-g-PLL) nanoparticles as TNF-α nanocarriers: potential cerebral ischemia/reperfusion injury therapeutic applications

Brain ischemia/reperfusion (I/R) injury (BI/RI) is a leading cause of death and disability worldwide. However, the outcome of pharmacotherapy for BI/RI remains unsatisfactory. Innovative approaches for enhancing drug sensitivity and recovering neuronal activity in BI/RI treatment are urgently needed. The purpose of this study was to evaluate the protective effects of tumor necrosis factor (TNF)-α-loaded poly(ethylene glycol)-b-(poly(ethylenediamine L-glutamate)-g-poly(L-lysine)) (TNF-α/PEG-b-(PELG-g-PLL)) nanoparticles on BI/RI. The particle size of PEG-b-(PELG-g-PLL) and the loading and release rates of TNF-α were determined. The nanoparticle cytotoxicity was evaluated in vitro using rat cortical neurons. Sprague Dawley rats were preconditioned with free TNF-α or TNF-α/PEG-b-(PELG-g-PLL) polyplexes and then subjected to 2 hours ischemia and 22 hours reperfusion. Brain edema was assessed using the brain edema ratio, and the antioxidative activity was assessed by measuring the superoxide dismutase (SOD) activity and the malondialdehyde (MDA) content in the brain tissue. We further estimated the inflammatory activity and apoptosis level by determining the levels of interleukin-4 (IL-4), IL-6, IL-8, IL-10, and nitric oxide (NO), as well as the expression of glial fibrillary acidic protein (GFAP), intercellular adhesion molecule-1 (ICAM-1), and cysteine aspartase-3 (caspase-3), in the brain tissue. We provide evidence that TNF-α preconditioning attenuated the oxidative stress injury, the inflammatory activity, and the apoptosis level in I/R-induced cerebral injury, while the application of block copolymer PEG-b-(PELG-g-PLL) as a potential TNF-α nanocarrier with sustained release significantly enhanced the bioavailability of TNF-α. We propose that the block copolymer PEG-b-(PELG-g-PLL) may function as a potent nanocarrier for augmenting BI/RI pharmacotherapy, with unprecedented clinical benefits. Further studies are needed to better clarify the underlying mechanisms.