Protective effect of ginkgolide B against acute spinal cord injury in rats and its correlation with the Jak/STAT signaling pathway

Neuroprotective effect and possible mechanisms of the extract of ginkgo biloba for spinal cord injury in experimental animal: a meta-analysis and systematic review

Spinal cord injury (SCI) is a major challenge in the medical community because of its difficulty in treatment and poor prognosis. Extract of ginkgo biloba (EGb) has been widely used in the prevention and treatment of age-related neurosensory disease, which is considered to have the effect of neuroprotection. We performed a systematic review to evaluate the neurobiological roles of EGb for treating SCI in rats. Pubmed, Embase, Sinomed and China National knowledge Infrastructure were searched from their inception dates to April 2024, and 30 articles were included. The quality score of the included studies ranged from 4 to 7 out of 10 points, and all of them were randomization. It was shown that after SCI, EGb administration could significantly improve motor function (WMD = 2.09 [1.59, 2.59], p < 0.00001). Subgroup analysis concluded that EGb at the doses of 10-50 mg/kg improved the motor function to the greatest extent. In comparison with the control group, EGb administration could reduce lipid peroxidation and inhibit inflammation (MDA: SMD = -1.43 [-5.05,2.20], p < 0.00001; iNOS: WMD = -22.17 [-35.45, -8.90], p < 0.00001). In addition, this review suggested that EGb can antagonize inflammation, reduce oxidative stress to inhibit the lipid peroxidation and resistance to apoptosis, promote nerve growth and reduce myelin loss on SCI. Preclinical grade suggests that, collectively, EGb may be a promising natural neuroprotective agent on SCI with unique advantages and mechanisms of action. More clinical randomized, blind controlled trials are also needed to confirm the neuroprotective effect of EGb on SCI.

Recent advances on signaling pathways and their inhibitors in spinal cord injury

Spinal cord injury (SCI) is a serious and disabling central nervous system injury. Its complex pathological mechanism can lead to sensory and motor dysfunction. It has been reported that signaling pathway plays a key role in the pathological process and neuronal recovery mechanism of SCI. Such as PI3K/Akt, MAPK, NF-κB, and Wnt/β-catenin signaling pathways. According to reports, various stimuli and cytokines activate these signaling pathways related to SCI pathology, thereby participating in the regulation of pathological processes such as inflammation response, cell apoptosis, oxidative stress, and glial scar formation after injury. Activation or inhibition of relevant pathways can delay inflammatory response, reduce neuronal apoptosis, prevent glial scar formation, improve the microenvironment after SCI, and promote neural function recovery. Based on the role of signaling pathways in SCI, they may be potential targets for the treatment of SCI. Therefore, understanding the signaling pathway and its inhibitors may be beneficial to the development of SCI therapeutic targets and new drugs. This paper mainly summarizes the pathophysiological process of SCI, the signaling pathways involved in SCI pathogenesis, and the potential role of specific inhibitors/activators in its treatment. In addition, this review also discusses the deficiencies and defects of signaling pathways in SCI research. It is hoped that this study can provide reference for future research on signaling pathways in the pathogenesis of SCI and provide theoretical basis for SCI biotherapy.

Targeted Therapy of Spinal Cord Injury: Inhibition of Apoptosis Is a Promising Therapeutic Strategy

Spinal cord injury (SCI) is a serious disabling central nervous system injury that can lead to motor, sensory, and autonomic dysfunction below the injury level. SCI can be divided into primary injury and secondary injury according to pathological process. Primary injury is mostly irreversible, while secondary injury is a dynamic regulatory process. Apoptosis is an important pathological event of secondary injury and has a significant effect on the recovery of nerve function after SCI. Nerve cell death can further aggravate the microenvironment of the injured site, leading to neurological dysfunction and thus affect the clinical outcome of patients. Therefore, apoptosis plays a crucial role in the pathological progression of secondary SCI, while inhibiting apoptosis may be a promising therapeutic strategy for SCI. This review will summarize and explore the factors that lead to cell death after SCI, the influence of cross talk between signaling pathways and pathways involved in apoptosis and discuss the influence of apoptosis on SCI, and the therapeutic significance of targeting apoptosis on SCI. This review helps us to understand the role of apoptosis in secondary SCI and provides a theoretical basis for the treatment of SCI based on apoptosis.

Ginkgolide B can alleviate spinal cord glymphatic system dysfunction and provide neuroprotection in painful diabetic neuropathy rats by inhibiting matrix metalloproteinase-9

The glymphatic system plays a crucial role in maintaining optimal central nervous system (CNS) function by facilitating the removal of metabolic wastes. Aquaporin-4 (AQP4) protein, predominantly located on astrocyte end-feet, is a key pathway for metabolic waste excretion. β-Dystroglycan (β-DG) can anchor AQP4 protein to the end-feet membrane of astrocytes and can be cleaved by matrix metalloproteinase (MMP)-9 protein. Studies have demonstrated that hyperglycemia upregulates MMP-9 expression in the nervous system, leading to neuropathic pain. Ginkgolide B (GB) exerts an inhibitory effect on the MMP-9 protein. In this study, we investigated whether inhibition of MMP-9-mediated β-DG cleavage by GB is involved in the regulation of AQP4 polarity within the glymphatic system in painful diabetic neuropathy (PDN) and exerts neuroprotective effects. The PDN model was established by injecting streptozotocin (STZ). Functional changes in the glymphatic system were observed using magnetic resonance imaging (MRI). The paw withdrawal threshold (PWT) was measured to assess mechanical allodynia. The protein expressions of MMP-9, β-DG, and AQP4 were detected by Western blotting and immunofluorescence. Our findings revealed significant decreases in the efficiency of contrast agent clearance within the spinal glymphatic system of the rats, accompanied by decreased PWT, increased MMP-9 protein expression, decreased β-DG protein expression, and loss of AQP4 polarity. Notably, GB treatment demonstrated the capacity to ameliorate spinal cord glymphatic function by modulating AQP4 polarity through MMP-9 inhibition, offering a promising therapeutic avenue for PDN.

The molecular mechanisms of ginkgo (Ginkgo biloba) activity in signaling pathways: A comprehensive review

BACKGROUND

One of the most unique plants that have ever grown on the planet is Ginkgo biloba L., a member of the Ginkgoaceae family with no close living relatives. The existence of several differently structured components of G. biloba has increased the chemical variety of herbal therapy. Numerous studies that investigated the biochemical characteristics of G. biloba suggest this plant as a potential treatment for many illnesses.

PURPOSE

Review the molecular mechanisms involved in the signaling pathways of G. biloba activity in varied circumstances and its potential as a novel treatment for various illnesses.

METHODS

Studies focusing on the molecular processes and signaling pathways of compounds and extracts of G. biloba were found and summarized using the proper keywords and operators from Google Scholar, PubMed, Web of Science, and Scopus without time restrictions.

RESULTS

G. biloba exerts its effects through its anti-inflammatory, anti-apoptotic, anti-cancer, neuroprotective, cardioprotective, hepatoprotective, antiviral, antibacterial, pulmoprotective, renoprotective, anti-osteoporosis, anti-melanogenic, retinoprotective, otoprotective, adipogenic, and anti-adipogenic properties. The most important mechanisms involved in these actions are altering the elevation of ROS formation, inhibiting NADPH oxidases activation, altering the expression of antioxidant enzymes, downregulating MAPKs (p38 MAPK and ERK, and JNK) and AP-1, increasing cAMP, inactivating Stat5, activating the AMPK signaling pathway, affecting Stat3/JAK2, NF-κB, Nrf-2, mTOR, HGF/c-Met, Wnt/β-catenin and BMP signaling pathways, and changing the mitochondrial transmembrane potential, the Bax/Bcl-2 ratio, the release of Cyc from mitochondria to cytosol, the protein cleavage of caspases 3, 7, 8, 9, and 12, poly (ADP-ribose) polymerase, and MMPs levels.

CONCLUSIONS

G. biloba and its components have gained attention in recent years for their therapeutic benefits, such as their anti-inflammatory, antioxidant, anti-apoptotic, and apoptotic effects. By understanding their molecular mechanisms and signaling pathways, potential novel medicines might be developed in response to the rising public desire for new therapies.

IL-6/JAK2/STAT3 axis mediates neuropathic pain by regulating astrocyte and microglia activation after spinal cord injury

After spinal cord injury (SCI), the control of activated glial cells such as microglia and astrocytes has emerged as a promising strategy for neuropathic pain management. However, signaling mechanism involved in glial activation in the process of neuropathic pain development and maintenance after SCI is not well elucidated. In this study, we investigated the potential role and mechanism of the JAK2/STAT3 pathway associated with glial cell activation in chronic neuropathic pain development and maintenance after SCI. One month after contusive SCI, the activation of JAK2/STAT3 pathway was markedly upregulated in both microglia and astrocyte in nociceptive processing regions of the lumbar spinal cord. In addition, both mechanical allodynia and thermal hyperalgesia was significantly inhibited by a JAK2 inhibitor, AG490. In particular, AG490 treatment inhibited both microglial and astrocyte activation in the lumbar (L) 4-5 dorsal horn and significantly decreased levels of p-p38MAPK, p-ERK and p-JNK, which are known to be activated in microglia (p-p38MAPK and p-ERK) and astrocyte (p-JNK). Experiments using primary cell cultures also revealed that the JAK2/STAT3 pathway promoted microglia and astrocyte activation after lipopolysaccharide stimulation. Furthermore, JAK2/STAT3 signaling and pain behaviors were significantly attenuated when the rats were treated with anti-IL-6 antibody. Finally, minocycline, a tetracycline antibiotic, inhibited IL-6/JAK2/STAT3 signaling pathway in activated glial cells and restored nociceptive thresholds and the hyperresponsiveness of dorsal neurons. These results suggest an important role of the IL-6/JAK2/STAT3 pathway in the activation of microglia and astrocytes and in the maintenance of chronic below-level pain after SCI.

Buyang Huanwu Decoction promotes the neurological recovery of traumatic spinal cord injury via inhibiting apoptosis, inflammation, and oxidative stress

BACKGROUND

The incidence rate of spinal cord injury (SCI) is increasing, and the mortality or disability rate caused by SCI remains high in the world. Buyang Huanwu Decoction (BYHWD) is a kind of Traditional Chinese medicine, and it is believed to be effective in several kinds of nervous system diseases. Whether BYHWD could improve SCI and the potential function mechanism remain unclear.

METHODS

SCI animal model was established by damaging T10 spinal cord. Animals experiments included five groups as follows: Sham, SCI, SCI+BYHWD, SCI+mesenchymal stromal cells (MSCs), and SCI+BYHWD+MSCs. H2 O2 -treated cells (100 µM, 6 h) were used to simulate SCI damage in vitro, which included five groups as follows: control, H2 O2 , H2 O2 +BYHWD, H2 O2 +MSCs, and H2 O2 +BYHWD+MSCs. The behavioral function was evaluated with Tarlov and inclined plated test score. Western blot analysis and immunohistochemical staining were used to detect protein expression. The levels of superoxide dismutase (SOD), catalase (CAT), malondiadehyde (MDA), interleukin (IL)-1β, tumor necrosis factor-α, and IL-6 in serum were measured with commercial enzyme-linked immunosorbent assay kits. terminal deoxynucleotidyl transferase dUTP nick end labeling staining and flow cytometry were performed to measure apoptosis in vivo and in vitro levels. Gene expression profiling analysis was performed to analyze differential expression genes.

RESULTS

BYHWD suppressed apoptosis and accelerating cell proliferation after SCI. Recovery of neurofunction, inhibition of inflammatory response, and oxidative condition were achieved by BYHWD and MSCs. The expression levels of gp130/Janus kinase/signal transducers and activator of transcription (JAK/STAT) were suppressed by BYHWD and MSCs, both in vivo and in vitro. BYHWD and MSCs markedly promoted cells viability and inhibited apoptosis. Greater gene expression difference was observed between group control and H2 O2 through gene expression profiling analysis. The recovery effects of traumatic SCI by BYHWD were similar to MSCs, and synergies effects were observed in several items.

CONCLUSION

BYHWD could increase Tarlov score and Basso, Beatie, and Bresnahan functional score, inhibit apoptosis, inflammatory response, and oxidative condition after SCI. The expression level of gp130/JAK/STAT axis was suppressed by BYHWD. BYHWD might be a new therapeutic strategy for the prevention or treatment of SCI.

Ginkgo biloba in the management of the COVID-19 severity

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection is linked with inflammatory disorders and the development of oxidative stress in extreme cases. Therefore, anti-inflammatory and antioxidant drugs may alleviate these complications. Ginkgo biloba L. folium extract (EGb) is a herbal medicine containing various active constituents. This review aims to provide a critical discussion on the potential role of EGb in the management of coronavirus disease 2019 (COVID-19). The antiviral effect of EGb is mediated by different mechanisms, including blocking SARS-CoV-2 3-chymotrypsin-like protease that provides trans-variant effectiveness. Moreover, EGb impedes the development of pulmonary inflammatory disorders through the diminution of neutrophil elastase activity, the release of proinflammatory cytokines, platelet aggregation, and thrombosis. Thus, EGb can attenuate the acute lung injury and acute respiratory distress syndrome in COVID-19. In conclusion, EGb offers the potential of being used as adjuvant antiviral and symptomatic therapy. Nanosystems enabling targeted delivery, personalization, and booster of effects provide the opportunity for the use of EGb in modern phytotherapy.

Possible involvement of female sex steroid hormones in intracellular signal transduction mediated by cytokines following traumatic brain injury

INTRODUCTION

The aim of this study was to determine the anti-inflammatory effect of female sex hormones on the level of intracellular molecules of cytokine signaling pathway after diffuse traumatic brain injury (TBI) in ovariectomized rats.

METHODS

Female rats were divided into 10 groups: control, sham, TBI, Vehicle (oil), Vehicle E1 (33.3 µg/kg), E2 (1 mg / kg), P1 (1.7 mg/kg), P2 (8 mg / kg), E2 + P1. All drugs were injected 0.5 h after TBI. Brain edema and the brain levels of P-STAT-3, NFκB-P52, NFκB-P65, P-IκB, and SOCS-3 by immunohistochemistry measured at 24 h after TBI.

RESULTS

Increased brain edema after TBI was inhibited by different doses of estrogen, progesterone (P < 0.001), and E2 + P1 (P < 0.05). The brain levels of P-STAT-3, NFκB-P52, NFκB-P65, and p-IκBα that increased after TBI was decreased only by E2 (P < 0.05). E2 and E2 + P1 have increased the SOCS-3 level after TBI (P < 0.05). Also, there was a difference between the E2 with E1 and two progesterone doses (P < 0.05). So that in all cases, the effects of E2 were more significant than the other groups. The target cells for these effects of E2 were microglia and astrocytes.

CONCLUSION

The results indicate that one of the probable mechanism(s) of estrogen anti-inflammatory effect after TBI is either reduction of p-STAT-3, NFκB-P52, p-NFκB-P65, and p-IκBα or increase in SOCS-3 molecules involved in the signaling pathway of inflammatory cytokines.

MicroRNA-15a inhibits inflammatory response and apoptosis after spinal cord injury via targeting STAT3

OBJECTIVE

To clarify the function of microRNA-15a in the spinal cord injury (SCI) and its potential mechanism.

PATIENTS AND METHODS

The plasma levels of microRNA-15a and signal transducer and activator of transcription 3 (STAT3) in SCI patients were determined by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). The correlation between the expressions of microRNA-15a and STAT3 was analyzed. The in vitro SCI model was established in H2O2-induced C8-D1A and C8B4 cells, and in vivo SCI model was established in mice by hitting T10. The mRNA and protein expressions of tumor necrosis factor-α (TNF-α) and interleukin 6 (IL-6) were detected in the SCI model. The apoptosis was examined by flow cytometry or TUNEL staining, respectively. The motor function of mouse hindlimb was evaluated using the Basso Beattie Bresnahan (BBB) standard scale. The target gene of microRNA-15a was predicted by bioinformatics and further verified by dual-luciferase reporter gene assay. The expression changes of target genes in C8-D1A and C8B4 cells with microRNA-15a overexpression or knockdown were examined by qRT-PCR and Western blot. Finally, rescue experiments were performed to evaluate the regulatory effects of microRNA-15a and STAT3 on cell apoptosis.

RESULTS

MicroRNA-15a was lowly expressed in plasma of SCI patients, while STAT3 was highly expressed with a negative correlation to microRNA-15a. Identically, microRNA-15a was lowly expressed in H2O2-induced C8-D1A and C8B4 cells, and STAT3 was highly expressed. MicroRNA-15a overexpression downregulated mRNA and protein levels of TNF-α and IL-6 in C8-D1A and C8B4 cells. BBB score was markedly low in SCI mice relative to controls. SCI mice injected with microRNA-15a mimics had higher BBB score than those injected with negative control. Besides, SCI mice with microRNA-15a overexpression had downregulated expressions of STAT3, TNF-α, and IL-6 in the impaired spinal cord tissues, as well as lower apoptotic rate. Through bioinformatics, we found binding sites between STAT3 and microRNA-15a. Their binding conditions were further verified by dual-luciferase reporter gene assay. Moreover, STAT3 expression was negatively regulated by microRNA-15a. Finally, rescue experiments showed that STAT3 overexpression could reverse the regulatory effects of microRNA-15a on expressions of TNF-α and IL-6, as well as apoptosis.

CONCLUSIONS

MicroRNA-15a expression decreases in the SCI model, which participates in the process of SCI by regulating inflammatory response and cell apoptosis via targeting STAT3.

Harnessing the Secretome of Mesenchymal Stromal Cells for Traumatic Spinal Cord Injury: Multicell Comparison and Assessment of In Vivo Efficacy

Cell therapy offers significant promise for traumatic spinal cord injury (SCI), which despite many medical advances, has limited treatment strategies. Able to address the multifactorial and dynamic pathophysiology of SCI, cells present various advantages over standard pharmacological approaches. However, the use of live cells is also severely hampered by logistical and practical considerations. These include specialized equipment and expertise, standardization of cell stocks, sustained cell viability post-thawing, and cryopreservation-induced delayed-onset cell death. For this reason, we suggest a novel and clinically translatable alternative to live-cell systemic infusion, which retains the efficacy of the latter while overcoming many of its limitations. This strategy involves the administration of concentrated cell secretome and exploits the trophic mechanism by which stromal cells function. In this study, we compare the efficacy of intravenously delivered concentrated conditioned media (CM) from human umbilical cord matrix cells (HUCMCs), bone marrow mesenchymal stromal cells, as well as newborn and adult fibroblasts in a rat model of moderately severe cervical clip compression/contusion injury (C7--T1, 35 g). This is further paired with a thorough profile of the CM cytokines, chemokines, and angiogenic factors. The HUCMC-derived CM was most effective at limiting acute (48 h post-SCI) vascular pathology, specifically lesion volume, and functional vascularity. Principle component analysis (PCA), hierarchical clustering, and interaction analysis of proteins highly expressed in the HUCMC secretome suggest involvement of the MAPK/ERK, JAK/STAT, and immune cell migratory pathways. This "secretotherapeutic" strategy represents a novel and minimally invasive method to target multiple organ systems and several pathologies shortly after traumatic SCI.

Effects of Ginkgo biloba on Early Decompression after Spinal Cord Injury

Spinal cord injury (SCI) is a severe trauma of the central nervous system characterized by high disability and high mortality. Clinical progress has been achieved in understanding the pathological mechanism of SCI and its early treatment, but the results are unsatisfactory. In China, increasing attention has been paid to the role of traditional Chinese medicine in the treatment of SCI. In particular, extracts from the leaves of Ginkgo biloba (maidenhair tree), which have been reported to exert anti-inflammatory and antioxidant properties and repair a variety of active cellular damage, have been applied therapeutically for centuries. In this study, we established a rat SCI model to investigate the effects of Ginkgo biloba leaves on decompression at different stages of SCI. The application of Ginkgo biloba leaves during the decompression of SCI at different time points, the neurological recovery of SCI, and the underlying molecular mechanism were explored. The findings provide reliable experimental data that reveal the mechanism of GBI (Ginkgo biloba injection) in the clinical treatment of SCI.

Pectolinarigenin promotes functional recovery and inhibits apoptosis in rats following spinal cord injuries

Spinal cord injury (SCI) is a devastating neurological injury that frequently leads to neurological defects and disabilities. The only effective pharmacotherapy currently available is methylprednisolone (MP), which is controversial due to its high incidence of complications, adverse events and ultimately limited efficacy in SCI. Therefore, the development of alternative therapeutic agents for the treatment of SCI is of great clinical significance. In the present study, an acute SCI rat model was induced and, following a modified Allen method, the function of pectolinarigenin (PG) in SCI was investigated. A total of 36 rats were randomly divided into 6 groups (n=6 in each group); a sham surgery group and an SCI + saline group were used as negative controls and an SCI + MP (30 mg/kg) group was used as a positive control. The remaining animals were subdivided into three groups: SCI + PG (10 mg/kg); SCI + PG (30 mg/kg); and SCI + PG (50 mg/kg). Basso-Beattie-Bresnahan locomotor rating scoring was performed to assess functional recovery. Nissl staining and TUNEL staining were used to evaluated neuronal lesion volume and apoptosis, respectively. The results demonstrated that PG significantly improved functional recovery and reduced tissue loss, and neuronal apoptosis. Furthermore, a western blotting assay was conducted to measure the expression of genes associated with apoptosis. The data suggested that PG downregulated the activated caspase-3, caspase-9 and poly-ADP-ribose polymerase expression and reduced the Bax: Bcl2 ratio. The findings of the present study suggested that PG may exert a protective effect against SCI in rats, potentially by inhibiting neuronal apoptosis and PG may therefore serve as a novel therapeutic agent against SCI.

Identification of Chinese Herbal Compounds with Potential as JAK3 Inhibitors

The Janus kinases (JAKs) consist of four similar tyrosine kinases and function as key hubs in the signaling pathways that are implicated in both innate and adaptive immunity. Among the four members, JAK3 is probably the more attractive target for treatment of inflammatory diseases because its inhibition demonstrates the greatest immunosuppression and most profound effect in the treatment of such disorders. Although many JAK3 inhibitors are already available, certain shortcomings have been identified, mostly acquired drug resistance or unwanted side effects. To discover and identify new promising lead candidates, in this study, the structure of JAK3 (3LXK) was obtained from the Protein Data Bank and used for simulation modeling and protein-ligand interaction analysis. The ~36,000 Chinese herbal compounds obtained from TCM Database@Taiwan were virtually screened by AutoDock Vina docking program and filtered with Lipinski's Rules and ADME/T virtual predictions. Because of high occurrence of fake hits during docking, we selected 12 phytochemicals which have demonstrated modulating JAKs expressions among the top 50 chemicals from docking results. To validate whether these compounds are able to directly mediate JAK3 kinase, we have investigated the inhibitory activity using enzymatic activity assays, western blot, and HEK 293 cell STAT5 transactivity assays. The molecular analysis included docking and molecular dynamics (MD) simulations in order to investigate structural conformations and to explore the key amino acids in the interaction between JAK3 kinase and its putative ligands. The results demonstrated that Cryptotanshinone, Icaritin, and Indirubin exhibited substantial inhibitory activity against JAK3 kinase in vitro. The results also provide binding models of the protein-ligand interaction, detailing the interacting amino acid residues at the active ATP-binding domains of JAK3 kinase. In conclusion, our work discovered 3 potential natural inhibitors of JAK3 kinase and could provide new possibilities and stimulate new insights for the treatment of JAK3-targeted diseases.

Early Optic Nerve Head Glial Proliferation and Jak-Stat Pathway Activation in Chronic Experimental Glaucoma

PURPOSE

We previously reported increased expression of cell proliferation and Jak-Stat pathway-related genes in chronic experimental glaucoma model optic nerve heads (ONH) with early, mild injury. Here, we confirm these observations by localizing, identifying, and quantifying ONH cellular proliferation and Jak-Stat pathway activation in this model.

METHODS

Chronic intraocular pressure (IOP) elevation was achieved via outflow pathway sclerosis. After 5 weeks, ONH longitudinal sections were immunolabeled with proliferation and cell-type markers to determine nuclear densities in the anterior (unmyelinated) and transition (partially myelinated) ONH. Nuclear pStat3 labeling was used to detect Jak-Stat pathway activation. Nuclear density differences between control ONH (uninjected) and ONH with either early or advanced injury (determined by optic nerve injury grading) were identified by ANOVA.

RESULTS

Advanced injury ONH had twice the nuclear density (P < 0.0001) of controls and significantly greater astrocyte density in anterior (P = 0.0001) and transition (P = 0.006) ONH regions. An increased optic nerve injury grade positively correlated with increased microglia/macrophage density in anterior and transition ONH (P < 0.0001, both). Oligodendroglial density was unaffected. In glaucoma model ONH, 80% of anterior and 66% of transition region proliferating cells were astrocytes. Nuclear pStat3 labeling significantly increased in early injury anterior ONH, and 95% colocalized with astrocytes.

CONCLUSIONS

Astrocytes account for the majority of proliferating cells, contributing to a doubled nuclear density in advanced injury ONH. Jak-Stat pathway activation is apparent in the early injury glaucoma model ONH. These data confirm dramatic astrocyte cell proliferation and early Jak-Stat pathway activation in ONH injured by elevated IOP.

Ginkgolide B promotes neuronal differentiation through the Wnt/β-catenin pathway in neural stem cells of the postnatal mammalian subventricular zone

Chinese herbal medicines (CHMs) have been used to treat human diseases for thousands of years. Among them, Ginkgo biloba is reported to be beneficial to the nervous system and a potential treatment of neurological disorders. Since the presence of adult neural stem cells (NSCs) brings hope that the brain may heal itself, whether the effect of Ginkgo biloba is on NSCs remains elusive. In this study, we found that Ginkgo biloba extract (GBE) and one of its main ingredients, ginkgolide B (GB) promoted cell cycle exit and neuronal differentiation in NSCs derived from the postnatal subventricular zone (SVZ) of the mouse lateral ventricle. Furthermore, the administration of GB increased the nuclear level of β-catenin and activated the canonical Wnt pathway. Knockdown of β-catenin blocked the neurogenic effect of GB, suggesting that GB promotes neuronal differentiation through the Wnt/β-catenin pathway. Thus, our data provide a potential mechanism underlying the therapeutic effect of GBE or GB on brain injuries and neurodegenerative disorders.

Neuroprotective Effect of CeO2@PAA-LXW7 Against H2O2-Induced Cytotoxicity in NGF-Differentiated PC12 Cells

CeO₂ nanoparticles (nanoceria) have been used in many studies as a powerful free radical scavenger, and LXW7, a small-molecule peptide, can specifically target the integrin αvβ3, whose neuroprotective effects have also been demonstrated. The objective of this study is to observe the neuroprotective effect and potential mechanism of CeO₂@PAA-LXW7, a new compound that couples CeO₂@PAA (nanoceria modified with the functional group of polyacrylic acid) with LXW7 via a series of chemical reactions, in H₂O₂-induced NGF-differentiated PC12 cells. We examined the effects of LXW7, CeO₂@PAA, and CeO₂@PAA-LXW7 on the viability of primary hippocampal neurons and found that there was no significant difference under control conditions, but increased cellular viability was observed in the case of H₂O₂-induced injury. We used H₂O₂-induced NGF-differentiated PC12 cells as the classical injury model to investigate the neuroprotective effect of CeO₂@PAA-LXW7. In this study, LXW7, CeO₂@PAA, and CeO₂@PAA-LXW7 inhibit H₂O₂-induced oxidative stress by reducing the production of reactive oxygen species (ROS) and regulating Bax/Bcl-2, cleaved caspase-3 and mitochondrial cytochrome C (cyto C) in the apoptotic signaling pathways. We found that the levels of phosphorylation of focal adhesion kinase (FAK) and of signal transducer and activator of transcription 3 (STAT3) increased significantly in H₂O₂-induced NGF-differentiated PC12 cells, whereas LXW7, CeO₂@PAA, and CeO₂@PAA-LXW7 suppressed the increase to different degrees. Among the abovementioned changes, the inhibitory effect of CeO₂@PAA-LXW7 on H₂O₂-induced changes, including the increases in the levels of p-FAK and p-STAT3, is more obvious than that of LXW7 or CeO₂@PAA alone. In summary, these results suggest that integrin signaling participates in the regulation of apoptosis via the regulation of ROS and of the apoptosis pathway in H₂O₂-induced NGF-differentiated PC12 cells. LXW7, CeO₂@PAA, and CeO₂@PAA-LXW7 can play neuroprotective roles by counteracting the oxidative stress and apoptosis induced by H₂O₂ in NGF-differentiated PC12 cells. CeO₂@PAA-LXW7 exerting a more powerful synergistic effect via the conjunction of LXW7 and CeO₂@PAA.

Mechanisms of autophagy and apoptosis mediated by JAK2 signaling pathway after spinal cord injury of rats

The aim of this study was to investigate the pathogenesis of autophagy and apoptosis mediated by Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) signal pathway after the onset of acute spinal cord injury (ASCI). A total of 45 Sprague-Dawley adult rats of either sex were selected for this study. The age of rats ranged from 8 to 10 weeks, and the average weight was 245 g. These rats were randomly divided into three groups, i.e. sham-operated group, model group, and the AG-490 intervention group (AG-490 is an inhibitor of JAK2). Each group contained 15 rats. Models were prepared using the modified Allen method. Five rats in each group were sacrificed at 6, 12 and 24 h, respectively, and the expression levels of p-JAK2 and p-STAT3 were detected in spinal cord tissue via western blot analysis. The levels of proinflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were detected via ELISA, positive expression of light chain 3 (LC3)-II of microtubule-associated protein 1 via immunofluorescence labeling method, and mRNA expression levels of caspase-3 and Bax/Bcl-2 via RT-PCR. In the model group, the expression levels of p-JAK2, p-STAT3, IL-6, TNF-α and LC3-II, and the mRNA expression levels of caspase-3 and Bax/Bcl-2 at all time-points were significantly higher than those in the AG-490 intervention group, and the levels in the sham-operated group were the lowest (p<0.05). In the model group, peak levels of p-JAK2 and p-STAT3 were attained at 12 h, but a decline was seen at 24 h; while increasing trend was seen in other indicators. In conclusion, JAK2/STAT3 signal pathway can mediate the activity of autophagy and apoptosis in an early stage after the onset of ASCI of rat.

Resveratrol, an antioxidant, protects spinal cord injury in rats by suppressing MAPK pathway

Resveratrol, a polyphenol found in various plants, including grapes, plums and peanuts has shown various medIRInal properties, including antioxidant, protection of cardiovascular disease and cancer risk. However, the effects of resveratrol on spinal cord reperfusion injury have not been investigated. Hence, the present study was designed to evaluate the effect of resveratrol on nitric oxide synthase (iNOS)/p38MAPK signaling pathway and to elucidate its regulating effect on the protection of spinal cord injury. Spinal cord ischemia–reperfusion injury (IRI) was performed by the infrarenal abdominal aorta with mini aneurysm clip model. The expressions of iNOS and p38MAPK and the levels of biochemical parameters, including nitrite/nitrate, malondialdehyde (MDA), advanced oxidation products (AOPP), reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) were measured in control and experimental groups. IRI-induced rats treated with 10 mg/kg resveratrol protected spinal cord from ischemia injury as supported by improved biological parameters measured in spinal cord tissue homogenates. The resveratrol treatment significantly decreased the levels of plasma nitrite/nitrate, iNOS mRNA and protein expressions and phosphorylation of p38MAPK in IRI-induced rats. Further, IRI-produced free radicals were reduced by resveratrol treatment by increasing enzymatic and non-enzymatic antioxidant levels such as GSH, SOD and CAT. Taken together, administration of resveratrol protects the damage caused by spinal cord ischemia with potential mechanism of suppressing the activation of iNOS/p38MAPK pathway and subsequent reduction of oxidative stress due to IRI.

Therapeutic Effects of Traditional Chinese Medicine on Spinal Cord Injury: A Promising Supplementary Treatment in Future

Objective. Spinal cord injury (SCI) is a devastating neurological disorder caused by trauma. Pathophysiological events occurring after SCI include acute, subacute, and chronic phases, while complex mechanisms are comprised. As an abundant source of natural drugs, Traditional Chinese Medicine (TCM) attracts much attention in SCI treatment recently. Hence, this review provides an overview of pathophysiology of SCI and TCM application in its therapy. Methods. Information was collected from articles published in peer-reviewed journals via electronic search (PubMed, SciFinder, Google Scholar, Web of Science, and CNKI), as well as from master's dissertations, doctoral dissertations, and Chinese Pharmacopoeia. Results. Both active ingredients and herbs could exert prevention and treatment against SCI, which is linked to antioxidant, anti-inflammatory, neuroprotective, or antiapoptosis effects. The detailed information of six active natural ingredients (i.e., curcumin, resveratrol, epigallocatechin gallate, ligustrazine, quercitrin, and puerarin) and five commonly used herbs (i.e., Danshen, Ginkgo, Ginseng, Notoginseng, and Astragali Radix) was elucidated and summarized. Conclusions. As an important supplementary treatment, TCM may provide benefits in repair of injured spinal cord. With a general consensus that future clinical approaches will be diversified and a combination of multiple strategies, TCM is likely to attract greater attention in SCI treatment.

Current Perspectives on the Beneficial Role of Ginkgo biloba in Neurological and Cerebrovascular Disorders

Ginkgo biloba extract is an alternative medicine available as a standardized formulation, EGb 761^®, which consists of ginkgolides, bilobalide, and flavonoids. The individual constituents have varying therapeutic mechanisms that contribute to the pharmacological activity of the extract as a whole. Recent studies show anxiolytic properties of ginkgolide A, migraine with aura treatment by ginkgolide B, a reduction in ischemia-induced glutamate excitotoxicity by bilobalide, and an alternative antihypertensive property of quercetin, among others. These findings have been observed in EGb 761 as well and have led to clinical investigation into its use as a therapeutic for conditions such as cognition, dementia, cardiovascular, and cerebrovascular diseases. This review explores the therapeutic mechanisms of the individual EGb 761 constituents to explain the pharmacology as a whole and its clinical application to cardiovascular and neurological disorders, in particular ischemic stroke.

The role of pharmacotherapy in modifying the neurological status of patients with spinal and spinal cord injuries

The aim here was to conduct a review of the literature on pharmacological therapies for modifying the neurological status of patients with spinal cord injuries. The PubMed database was searched for articles with the terms "spinal cord injury AND methylprednisolone/GM1/apoptosis inhibitor/calpain inhibitor/naloxone/tempol/tirilazad", in Portuguese or in English, published over the last five years. Older studies were included because of their historical importance. The pharmacological groups were divided according to their capacity to interfere with the physiopathological mechanisms of secondary injuries. Use of methylprednisolone needs to be carefully weighed up: other anti-inflammatory agents have shown benefits in humans or in animals. GM1 does not seem to have greater efficacy than methylprednisolone, but longer-term studies are needed. Many inhibitors of apoptosis have shown benefits in in vitro studies or in animals. Naloxone has not shown benefits. Tempol inhibits the main consequences of oxidation at the level of the spinal cord and other antioxidant drugs seem to have an effect superior to that of methylprednisolone. There is an urgent need to find new treatments that improve the neurological status of patients with spinal cord injuries. The benefits from treatment with methylprednisolone have been questioned, with concerns regarding its safety. Other drugs have been studied, and some of these may provide promising alternatives. Additional studies are needed in order to reach conclusions regarding the benefits of these agents in clinical practice.

Attenuated Reactive Gliosis and Enhanced Functional Recovery Following Spinal Cord Injury in Null Mutant Mice of Platelet-Activating Factor Receptor

Platelet-activating factor (PAF) is a unique phosphoglycerine that mediates the biological functions of both immune and nervous systems. Excessive PAF plays an important role in neural injury via its specific receptor (PAFR). In this study, we hypothesized that PAF signaling activates reactive gliosis after spinal cord injury (SCI), and blocking the PAF pathway would modify the glia scar formation and promote functional recovery. PAF microinjected into the normal wild-type spinal cord induced a dose-dependent activation of microglia and astrocytes. In the SCI mice, PAFR null mutant mice showed a better functional recovery in grip and rotarod performances than wild-type mice. Although both microglia and astrocytes were activated after SCI in wild-type and PAFR null mutant mice, expressions of IL-6, vimentin, nestin, and GFAP were not significantly elevated in PAFR null mutants. Disruption of PAF signaling inhibited the expressions of proteoglycan CS56 and neurocan (CSPG3). Intriguingly, compared to the wild-type SCI mice, less axonal retraction/dieback at 7 dpi but more NFH-labeled axons at 28 dpi was found in the area adjacent to the epicenter in PAFR null mutant SCI mice. Moreover, treatment with PAFR antagonist Ginkgolide B (GB) at the chronic phase rather than acute phase enhanced the functional recovery in the wild-type SCI mice. These findings suggest that PAF signaling participates in reactive gliosis after SCI, and blocking of this signaling enhances functional recovery and to some extent may promote axon regrowth.

Protective Effects and Mechanisms of Salvianolic Acid B Against H₂O₂-Induced Injury in Induced Pluripotent Stem Cell-Derived Neural Stem Cells

Induced pluripotent stem cells (iPSCs) have the potential to differentiate into neural lineages. Salvianolic acid B (Sal B) is a commonly used, traditional Chinese medicine for enhancing neuroprotective effects, and has antioxidant, anti-inflammatory, and antiapoptotic properties. Here, we explore the potential mechanism of Sal B in protecting iPSC-derived neural stem cells (NSCs) against H2O2-induced injury. iPSCs were induced into NSCs, iPSC-derived NSCs were treated with 50 μM Sal B for 24.5 h and 500 μM H2O2 for 24 h. The resulting effects were examined by flow cytometry analysis, quantitative reverse-transcription polymerase chain reaction, and western blotting. Upon H2O2 exposure, Sal B significantly promoted cell viability and stabilization of the mitochondrial membrane potential. Sal B also visibly decreased the cell apoptotic ratio. In addition, Sal B markedly reduced expression of matrix metalloproteinase (MMP)-2 and -9, and phosphospecific signal transducer and activator of transcription 3 (p-STAT3), and increased the level of tissue inhibitor of metalloproteinase (TIMP)-2 in iPSC-derived NSCs induced by H2O2. These results suggest that Sal B protects iPSC-derived NSCs against H2O2-induced oxidative stress. The mechanisms of this stress tolerance may be attributed to modulation of the MMP/TIMP system and inhibition of the STAT3 signaling pathway.

STAT3 inhibitor WP1066 as a novel therapeutic agent for bCCI neuropathic pain rats

Activation of signal transducer and activator of transcription-3 (STAT3) is suggested to be critically involved in the development of chronic pain, but the complex regulation of STAT3-dependent pathway and the functional significance of inhibiting this pathway during the development of neuropathic pain remain elusive. To evaluate the contribution of the JAK2/STAT3 pathway to neuropathic pain and the potentiality of this pathway as a novel therapeutic target, we examined the effects of the STAT3 inhibitor WP1066 by intrathecal administration in a rat model of bilateral chronic constriction injury (bCCI). The pain behavior tests were performed before the surgery and on postoperative day 3, 7, 14 and 21. L4-L6 dorsal spinal cord were harvested at each time point. Both RT-PCR and Western blot were performed to evaluate the activation of JAK2/STAT3 pathway. To observe the influence of WP1066 on neuropathic pain and its molecular mechanism, WP1066 (10 μl, 10 mmol/L in DMSO) or the same capacity of DMSO as the control were applied through the intrathecal tube on the day before bCCI surgery, and on the postoperative day 3 and 5. Behavioral tests were performed to observe the therapeutic effect on mechanical, thermal and cold hyperalgesia. L4-L6 dorsal spinal cord was harvested on postoperative day fourteen, followed by RT-PCR and Western blot evaluation of the JAK2/STAT3 pathway activation. The mechanical, thermal and cold hyperalgesia of the bCCI rats were significantly decreased when compared with the Sham or the Naïve group at each postoperative time point (P<0.05). JAK2 mRNA and STAT3 mRNA were significantly increased in the bCCI rats, accompanied by SOCS3 mRNA with a similar tendency. Western blot analysis showed that JAK2 and phosphorylated STAT3 increased significantly since 3 days after bCCI. JAK2 peaked on postoperative day 14 while phosphorylated STAT3 peaked on postoperative day 7 and gradually decreased thereafter and SOCS3׳s peak level on postoperative day 3. When WP1066 were administered intrathecally, the pain behaviors of the bCCI rats were significantly improved (P<0.05). WP1066 also inhibited the mRNA level of JAK2, STAT3 and SOCS3 in bCCI rats significantly, together with the protein level of JAK2, phosphorylated STAT3 and SOCS3 on postoperative day 14 as well. Our results found that the JAK2/STAT3 pathway in the spinal cord dorsal horn was significantly activated in the bCCI neuropathic pain rats. WP1066, which inhibited the STAT3 pathway specifically, could partially alleviate the pain behavior of the bCCI rats. So it may serve as a novel therapeutic strategy against neuropathic pain.

Conditioned medium from bone marrow-derived mesenchymal stem cells improves recovery after spinal cord injury in rats: an original strategy to avoid cell transplantation

Spinal cord injury triggers irreversible loss of motor and sensory functions. Numerous strategies aiming at repairing the injured spinal cord have been studied. Among them, the use of bone marrow-derived mesenchymal stem cells (BMSCs) is promising. Indeed, these cells possess interesting properties to modulate CNS environment and allow axon regeneration and functional recovery. Unfortunately, BMSC survival and differentiation within the host spinal cord remain poor, and these cells have been found to have various adverse effects when grafted in other pathological contexts. Moreover, paracrine-mediated actions have been proposed to explain the beneficial effects of BMSC transplantation after spinal cord injury. We thus decided to deliver BMSC-released factors to spinal cord injured rats and to study, in parallel, their properties in vitro. We show that, in vitro, BMSC-conditioned medium (BMSC-CM) protects neurons from apoptosis, activates macrophages and is pro-angiogenic. In vivo, BMSC-CM administered after spinal cord contusion improves motor recovery. Histological analysis confirms the pro-angiogenic action of BMSC-CM, as well as a tissue protection effect. Finally, the characterization of BMSC-CM by cytokine array and ELISA identified trophic factors as well as cytokines likely involved in the beneficial observed effects. In conclusion, our results support the paracrine-mediated mode of action of BMSCs and raise the possibility to develop a cell-free therapeutic approach.