Neuroprotective effect of salvianolate on cerebral ischaemia-reperfusion injury in rats by inhibiting the Caspase-3 signal pathway

Neuroprotective effects of the salidroside derivative SHPL-49 via the BDNF/TrkB/Gap43 pathway in rats with cerebral ischemia

Ischemic stroke is a common intravascular disease and one of the leading causes of death and disability. The salidroside derivative SHPL-49, which we previously synthesized, significantly attenuates cerebral ischemic injury in a rat model of permanent middle cerebral artery occlusion. To explore the neuroprotective mechanism of SHPL-49, the effects of SHPL-49 on the expression levels of neurotrophic factors in neurons and microglia and the polarization of microglia were investigated in the present study. SHPL-49 activated the brain-derived neurotrophic factor (BDNF) pathway, decreased the number of degenerated neurons, and accelerated neurogenesis in rats with cerebral ischemia. In addition, SHPL-49 promoted the polarization of microglia toward the M2 phenotype to alleviate neuroinflammation. In BV2 cells, SHPL-49 upregulated CD206 mRNA and protein levels and inhibited CD86 mRNA and protein levels. SHPL-49 also increased neurotrophic factor secretion in BV2 cells, which indirectly promoted the survival of primary neurons after oxygen-glucose deprivation (OGD). Proteomics analysis revealed that SHPL-49 promoted growth-associated protein 43 (Gap43) expression. SHPL-49 enhanced synaptic plasticity and increased Gap43 protein levels via activation of the BDNF pathway in the OGD primary neuron model. These results indicate that SHPL-49 prevents cerebral ischemic injury by activating neurotrophic factor pathways and altering microglial polarization. Thus, SHPL-49 is a potential neuroprotective agent.

Puerarin inhibited oxidative stress and alleviated cerebral ischemia-reperfusion injury through PI3K/Akt/Nrf2 signaling pathway

Introduction: Puerarin (PUE) is a natural compound isolated from Puerariae Lobatae Radix, which has a neuroprotective effect on IS. We explored the therapeutic effect and underlying mechanism of PUE on cerebral I/R injury by inhibiting oxidative stress related to the PI3K/Akt/Nrf2 pathway in vitro and in vivo. Methods: The middle cerebral artery occlusion and reperfusion (MCAO/R) rats and oxygen-glucose deprivation and reperfusion (OGD/R) were selected as the models, respectively. The therapeutic effect of PUE was observed using triphenyl tetrazolium and hematoxylin-eosin staining. Tunel-NeuN staining and Nissl staining to quantify hippocampal apoptosis. The reactive oxygen species (ROS) level was detected by flow cytometry and immunofluorescence. Biochemical method to detect oxidative stress levels. The protein expression related to PI3K/Akt/Nrf2 pathway was detected by using Western blotting. Finally, co-immunoprecipitation was used to study the molecular interaction between Keap1 and Nrf2. Results: In vivo and vitro studies showed that PUE improved neurological deficits in rats, as well as decreased oxidative stress. Immunofluorescence and flow cytometry indicated that the release of ROS can be inhibited by PUE. In addition, the Western blotting results showed that PUE promoted the phosphorylation of PI3K and Akt, and enabled Nrf2 to enter the nucleus, which further activated the expression of downstream antioxidant enzymes such as HO-1. The combination of PUE with PI3K inhibitor LY294002 reversed these results. Finally, co-immunoprecipitation results showed that PUE promoted Nrf2-Keap1 complex dissociation. Discussion: Taken together, PUE can activate Nrf2 via PI3K/Akt and promote downstream antioxidant enzyme expression, which could further ameliorate oxidative stress, against I/R-induced Neuron injury.

Multi-pathway neuroprotective effects of a novel salidroside derivative SHPL-49 against acute cerebral ischemic injury

SHPL-49 ((2R,3S,4S,5R,6R)-2-(hydroxymethyl)-6-(4-(4-methoxyphenyl) butoxy) tetrahydro-2H-pyran-3,4,5-triol) is a novel glycoside derivative obtained from structural modification of salidroside, which is isolated from the medicinal plant Rhodiola rosea L. SHPL-49 was administered to rats with permanent middle cerebral artery occlusion (pMCAO) for 5 days, and it was found that SHPL-49 could alleviate the cerebral infarct volume and reduce the neurological deficit score. Moreover, the effective time window of SHPL-49 in the pMCAO model was from 0.5 to 8 h after embolization. In addition, the result of immunohistochemistry showed that SHPL-49 could increase the number of neurons in the brain tissue and reduce the occurrence of apoptosis. Morris water maze and Rota-rod experiments showed that SHPL-49 could improve neurological deficits, repair neurocognitive and motor dysfunction, and enhance learning and memory ability in the pMCAO model after 14 days of SHPL-49 treatment. Further in vitro experiments showed that SHPL-49 significantly reduced the calcium overload of PC-12 cells and the production of reactive oxygen species (ROS) induced by oxygen and glucose deprivation (OGD), and increased the levels of antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), decreased the production of malondialdehyde (MDA). Furthermore, SHPL-49 could reduce cell apoptosis by increasing protein expression ratio of anti-apoptotic factor Bcl-2 to pro-apoptotic factor Bax in vitro. SHPL-49 also regulated the expression of Bcl-2 and Bax in ischemic brain tissue, and even inhibited the caspase cascade of pro-apoptotic proteins Cleaved-caspase 9 and Cleaved-caspase 3. Taken together, SHPL-49 exhibited neuroprotective effects against cerebral ischemic injury through multiple pathways, such as alleviating calcium overload, reducing oxidative stress damage, and inhibiting apoptosis.

Neuroprotective Effects and Metabolomics Study of Protopanaxatriol (PPT) on Cerebral Ischemia/Reperfusion Injury In Vitro and In Vivo

Stroke, one of the leading causes of disability and death worldwide, is a severe neurological disease that threatens human life. Protopanaxatriol (PPT), panaxatriol-type saponin aglycone, is a rare saponin that exists in Panax ginseng and Panax Noto-ginseng. In this study, we established an oxygen-glucose deprivation (OGD)-PC12 cell model and middle cerebral artery occlusion/reperfusion (MCAO/R) model to evaluate the neuroprotective effects of PPT in vitro and in vivo. In addition, metabolomics analysis was performed on rat plasma and brain tissue samples to find relevant biomarkers and metabolic pathways. The results showed that PPT could significantly regulate the levels of LDH, MDA, SOD, TNF-α and IL-6 factors in OGD-PC12 cells in vitro. PPT can reduce the neurological deficit score and infarct volume of brain tissue in rats, restore the integrity of the blood-brain barrier, reduce pathological damage, and regulate TNF-α, IL-1β, IL-6, MDA, and SOD factors. In addition, the results of metabolomics found that PPT can regulate 19 biomarkers involving five metabolic pathways, including amino acid metabolism, arachidonic acid metabolism, sphingolipid metabolism, and glycerophospholipid metabolism. Thus, it could be inferred that PPT might serve as a novel natural agent for MCAO/R treatment.

Toxicity mechanism of patulin on 293 T cells and correlation analysis of Caspase family

Patulin (PAT), a kind of mycotoxin, is a widely disseminated mycotoxin found in agricultural products. Although the existing research results show that PAT can cause nerve, immune, and skin toxicities, resulting in heart, liver, and kidney damages. However, evidence on the underlying mechanisms of PAT is still lacking. Present study aims to investigate the renal toxicity and related mechanisms of PAT on 293 T cells. Cell Counting Kit-8 method was used to reveal the dose-effect relationship and the time-effect relationship of PAT toxicity. Trypan blue staining and Hoechst 33342 staining were used to analyze PAT, which induced apoptosis on 293 T cells. Superoxide-dismutase (SOD), GSH, and malondialdehyde (MDA) were used to measure the changes of oxidative stress status of 293 T cells induced by PAT. The changes of reactive oxygen species (ROS) and ATP in mitochondria indicate the role of mitochondria when PAT induced cell damage and apoptosis. Through Cyt-C release assay analysis, caspase activity change, and correlation analysis, the potential mechanism of mitochondrial apoptosis pathway was proved. Results demonstrated that PAT significantly induced cell injury, and with the increase of time and concentration, the cell survival rate decreased significantly. Hoechst 33342 staining and Trypan blue staining showed that apoptosis rate was elevated by PAT. As PAT concentration increased, intracellular SOD, glutathion peroxidase activities were decreased and the MDA content was increased. The decrease of intracellular ATP level and accumulation of ROS content indicated an increased permeability of the mitochondrial membrane. Overexpression of Cyt-C activated the cascade reaction of caspase enzyme, leading to apoptosis. The results of enzyme activity assay and correlation analysis indicated that caspase 3 was the most critical caspase in the cascade system and that it was most correlated with caspase 8 and caspase 9.

Therapeutic targets by traditional Chinese medicine for ischemia-reperfusion injury induced apoptosis on cardiovascular and cerebrovascular diseases

Traditional Chinese medicine (TCM) has a significant role in treating and preventing human diseases. Ischemic heart and cerebrovascular injuries are two types of diseases with different clinical manifestations with high prevalence and incidence. In recent years, it has been reported that many TCM has beneficial effects on ischemic diseases through the inhibition of apoptosis, which is the key target to treat myocardial and cerebral ischemia. This review provides a comprehensive summary of the mechanisms of various TCMs in treating ischemic cardiovascular and cerebrovascular diseases through anti-apoptotic targets and pathways. However, clinical investigations into elucidating the pharmacodynamic ingredients of TCM are still lacking, which should be further demystified in the future. Overall, the inhibition of apoptosis by TCM may be an effective strategy for treating ischemic cardio-cerebrovascular diseases.

Challenges and Improvements of Novel Therapies for Ischemic Stroke

Stroke is the third most common disease all over the world, which is regarded as a hotspot in medical research because of its high mortality and morbidity. Stroke, especially ischemic stroke, causes severe neural cell death, and no effective therapy is currently available for neuroregeneration after stroke. Although many therapies have been shown to be effective in preclinical studies of ischemic stroke, almost none of them passed clinical trials, and the reasons for most failures have not been well identified. In this review, we focus on several novel methods, such as traditional Chinese medicine, stem cell therapy, and exosomes that have not been used for ischemic stroke till recent decades. We summarize the proposed basic mechanisms underlying these therapies and related clinical results, discussing advantages and current limitations for each therapy emphatically. Based on the limitations such as side effects, narrow therapeutic window, and less accumulation at the injury region, structure transformation and drug combination are subsequently applied, providing a deep understanding to develop effective treatment strategies for ischemic stroke in the near future.

Sodium tanshinone IIA sulfonate ameliorates cerebral ischemic injury through regulation of angiogenesis

Vascular remodeling and neuroprotection are two major adaptable methods for treating ischemic stroke. Edaravone is a protective agent for the treatment of stroke and was used as a positive control in the present study. Sodium tanshinone IIA sulfonate (STS) has demonstrated therapeutic clinical effects in cerebral infarction in China, while its mechanisms of action in ischemic stroke have remained elusive. The angiogenesis and neuroprotective effects of STS were evaluated in a rat model induced by middle cerebral artery occlusion and 3 days of reperfusion. When used at the same dose, the magnitude of the therapeutic effect of STS was similar to that of edaravone in terms of decreased blood-brain barrier damage as indicated by reduced Evans blue leakage, improved neurological deficits, alleviated cerebral edema and inhibition of histopathological changes caused by ischemia/reperfusion. The TUNEL assay demonstrated that the ability of STS to inhibit neuronal apoptosis was equivalent to that of edaravone. Immunofluorescence detection of CD31 and α-smooth muscle actin indicated that the vascular density was significantly reduced in the vehicle group compared with that in the sham operation group, STS increased the microvessel density in the ischemic area. Furthermore, in the vehicle group the protein expression of vascular endothelial growth factor (VEGF) and VEGF receptor 2 (VEGFR) as determined by fluorescence microscopy and immunohistochemistry was significantly reduced compared with that in the sham group. However, STS promoted their expression compared to the vehicle group respectively, and increaed the mRNA expression of VEGF, VEGFR, CD31 and angiopoietin-1 as determined by reverse transcription-quantitative PCR, but these changes were not significant or not present for edaravone apart from Ang-1. In conclusion, STS protected against ischemic brain injury by promoting angiogenesis in ischemic areas and inhibiting neuronal apoptosis. These results provide a potential treatment for stroke recovery.

Long Noncoding RNA H19 Overexpression Protects against Hypoxic-Ischemic Brain Damage by Inhibiting miR-107 and Up-Regulating Vascular Endothelial Growth Factor

Long noncoding RNAs play critical roles in cellular homeostasis, and long noncoding RNA H19 (H19) is implicated in several pathologic conditions. The putative role of H19 in the pathogenesis and progression of hypoxic-ischemic brain damage (HIBD) is not yet understood. Therefore, a series of in vivo and in vitro experiments were designed to investigate the potential roles of H19 in neuronal apoptosis and cognitive dysfunction in HIBD. H19 expression was decreased in HIBD rat models established by partial occlusion of carotid artery. H19 bound to and decreased the expression of miR-107, which also increased VEGF expression. H19 overexpression reduced neuronal apoptosis and alleviated cognitive dysfunction in HIBD rats. The up-regulation of miR-107 reversed the protective effects conferred by H19. In addition, the cell model of HIBD was established by oxygen-glucose deprivation in neuronal cells used. H19 overexpression in oxygen-glucose deprivation neurons increased B-cell lymphoma-2 and decreased B-cell lymphoma-2-associated X, total and cleaved caspase-3 expressions. Taken together, the results showed that H19 expresses at a low level in HIBD. H19 overexpression decreased miR-107 and increased VEGF expression, which resulted in repressed neuronal apoptosis and alleviated cognitive dysfunction. Thus, H19 may serve as a molecular target for translational research for HIBD therapy.