Combined Treatment with Fasudil and Menthol Improves Functional Recovery in Rat Spinal Cord Injury Model

The potential role of RhoA/ROCK-inhibition on locomotor recovery after spinal cord injury: a systematic review of in-vivo studies

STUDY DESIGN

Systematic Review.

OBJECTIVES

To thoroughly assess the existing literature regarding the impact of anti-RhoA/ROCK agents or procedures on functional recovery in animal models of SCI.

SETTING

Sina Trauma and Surgery Research Center, Tehran University of Medical Sciences.

METHODS

A comprehensive search was conducted in Ovid MEDLINE, Embase, Scopus, and Web of Science Core Collection utilizing a combination of keywords. All in-vivo animal studies of acute or chronic SCI that evaluated the pharmacological effects of Rho/ROCK inhibitors in English literature were included in this study.

RESULTS

Totally, 2320 articles were identified, of which, 60 papers were included for further analysis. A total of 47 (78%) studies were conducted merely on rats, 9 (15%) on mice, 3 (5%) used both, and the remaining used other animals. Y-27632, Fasudil, C3 Transferase and its derivatives (C3-05/PEP-C3/CT04/C3bot154-182/C3bot26mer(156-181)), Ibuprofen, Electroacupuncture (EA), SiRhoA, miR-133b, miR-135-5p, miR-381, miR-30b, Statins, 17β-estradiol, β-elemene, Lentivirus-mediated PGC-1a, Repulsive guidance molecule (RGMa), Local profound hypothermia, Jisuikang (JSK), Hyperbaric oxygen (HBO), Lv-shRhoA (Notch-1 inhibitor), Anti-Ryk antibody, LINGO-antagonist, BA-210, p21Cip1/WAF1, ORL-1 antagonist, Epigallocatechin-3-gallate (EGCG), Tamsulosin, AAV.ULK1.DN, and Indomethacin were the 28 reported agents/procedures with anti-RhoA/ROCK effects. The pooled SMD for BBB scores was 0.41 (p = 0.048) in the first week, 0.85 (p < 0.001) in the second week, 1.22 (p = 0.010) in the third week, and 1.53 (p = 0.001) in the fourth week.

CONCLUSION

Of the 28 identified anti-RhoA/ROCK agents, all but two (C3bot and its derivatives and EGCG) demonstrated promising results. The results of the meta-analysis cautiously indicate a significant increase in BBB scores over time after SCI.

Therapeutic potential of monoterpene molecules acts against 7KCh-mediated oxidative stress and neuroinflammatory amyloidogenic signalling pathways

Alzheimer's disease (AD) is a degenerative disorder characterised by amyloid-beta aggregates activated by the accumulation of lipid molecules and their derivatives, especially 7-ketocholesterol (7KCh), an oxidised lipid that plays a great part in the progression of AD. The current therapeutics need bio-potential molecules and their biomedical application preventing 7KCh-induced cytotoxicity. In this study, bornyl acetate (BA) and menthol (ME), the natural monoterpenes were investigated for their neuroprotective effects against 7KCh-induced SH-SY5Y cells and their effects were compared to the standard drug galantamine (GA). 7KCh-induced changes like lipid accumulation, amyloid generation, free radical generation, acetylcholinesterase levels, calcium accumulation and mitochondrial membrane integrity were analysed in SH-SY5Y cells with or without BA and ME treatment. Furthermore, various mediators involved in the amyloidogenic, inflammatory and apoptotic pathways were studied. In our results, the cells induced with 7KCh upon co-treatment with BA and ME significantly reduced lipid accumulation and amyloid generation through toll-like receptor (TLR) 4 suppression and enhanced ATP binding cassette (ABCA) 1-mediated clearance. Co-treatment with BA and ME concurrently regulated oxidative stress, acetylcholinesterase activity, mitochondrial membrane potential and intracellular calcification altered by 7KCh-induced SH-SY5Y cells. Moreover, 7KCh-induced cells showed elevated mRNA levels of misfolded protein markers and apoptotic mediators which were significantly downregulated by BA and ME co-treatment. In addition, the protein expression of amyloidogenic, proinflammatory as well as pro-apoptotic markers was decreased by BA and ME co-treatment in 7KCh-induced cells. Overall, BA and ME mediated inhibition of amyloidogenic activation and cell survival against 7KCh-induced inflammation, thereby preventing the onset and progression of AD in comparison to GA.

Protective effect of menthol against thioacetamide-induced hepatic encephalopathy by suppressing oxidative stress and inflammation, augmenting expression of BDNF and α7-nACh receptor, and improving spatial memory

Hepatic encephalopathy (HE) is a neuropsychiatric syndrome that can occur in people with acute or chronic liver disease. Here, we investigated the effects of menthol, a natural monoterpene, on HE induced by thioacetamide (TA) in male Wistar rats. The rats received 200 mg/kg of TA twice a week for four weeks and were administered 10 mg/kg of menthol intraperitoneally daily for the same period. The results showed that menthol treatment reduced oxidative stress and inflammation in the livers and hippocampi of the rats that received TA. It also lowered the levels of ammonium and liver enzymes AST, ALT, ALP, and GGT in the serum of these animals and prevented liver histopathological damage. In addition, the expression and activity of acetylcholinesterase in the hippocampus of HE model rats were decreased by menthol. Likewise, this monoterpene reduced the expression of TLR4, MyD88, and NF-κB in the hippocampus while increasing the expression of BDNF and α7-nACh receptor. Menthol also reduced neuronal death in the hippocampal cornu ammonis-1 and dentate gyrus regions and reduced astrocyte swelling, which led to improved learning and spatial memory in rats with HE. In conclusion, the study suggests that menthol may have strong protective effects on the liver and brain, making it a potential treatment for HE and neurodegenerative diseases.

Effects of fasudil on glial cell activation induced by tooth movement

BACKGROUND

Orthodontic pain affects the physical and mental health of patients. The spinal trigeminal subnucleus caudalis (SPVC) contributes to the transmission of pain information and serves as a relay station for integrating orofacial damage information. Recently, glial cells have been found to be crucial for both acute and maintenance phases of pain. It has also been demonstrated that rho kinase (ROCK) inhibitors can manage different pain models by inhibiting glial cell activation. Here, we hypothesized that orthodontic pain is related to glial cells in the SPVC, and Fasudil, a representative rho/rock kinase inhibitor, can relieve orthodontic pain by regulating the function of glial cells and the related inflammatory factors. In this study, we constructed a rat model of tooth movement pain and used immunofluorescence staining to evaluate the activation of microglia and astrocytes. Quantitative real-time PCR was used to detect the release of related cytokines and the expression of pain-related genes in the SPVC. Simultaneously, we investigated the effect of Fasudil on the aforementioned indicators.

RESULTS

In the SPVC, the expression of c-Fos peaked on day 1 along with the expression of OX42 (related to microglial activation), CD16 (a pro-inflammatory factor), and CD206 (an anti-inflammatory factor) on day 3 after tooth movement, followed by a gradual decrease. GFAP-staining showed that the number of activated astrocytes was the highest on day 5 and that cell morphology became complex. After Fasudil treatment, the expression of these proteins showed a downward trend. The mRNA levels of pro-inflammatory factors (IL-1β and TNF-α) peaked on day 3, and the mRNA expression of the anti-inflammatory factor TGF-β was the lowest 3 days after tooth movement. Fasudil inhibited the mRNA expression of pain-related genes encoding CSF-1, t-PA, CTSS, and BDNF.

CONCLUSION

This study shows that tooth movement can cause the activation of glial cells in SPVC, and ROCK inhibitor Fasudil can inhibit the activation of glial cells and reduce the expression of the related inflammatory factors. This study presents for the first time the potential application of Fasudil in othodontic pain.

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.

Improvement of spinal cord injury symptoms by targeting the Bax/Bcl2 pathway and modulating TNF-α/IL-10 using Platelet-Rich Plasma exosomes loaded with dexamethasone

Spinal cord injury (SCI) is a debilitating condition that results in impaired sensory and motor function due to the limited self-regenerative ability of the spinal cord. To address this issue, combination therapy has been proposed as an effective treatment strategy for SCI regeneration. In this study, Platelet-Rich Plasma (PRP)-derived exosomes loaded with dexamethasone were utilized in a mouse model of SCI compression. PRP-derived exosomes loaded with dexamethasone (Dex) were prepared using ultracentrifugation and sonication methods and were administered to the mice via intravenous injection. Following a four-week duration, behavioral assessments were administered to assess functional recuperation, and diverse metrics encompassing the expression of genes associated with apoptosis and antiapoptosis, serum cytokine concentrations and tissue sampling were subjected to thorough examination. The results of this study demonstrated that mice treated with PRP-derived exosomes loaded with Dex (ExoDex) exhibited altered levels of TNF-α and IL-10, along with decreased Bax and increased Bcl2 expression in comparison to the model group. Furthermore, intravenously injected ExoDex reduced the size of the lesion site, lymphocyte infiltration, vacuolation, cavity size and tissue disorganization while also improving locomotor recovery. We propose that the utilization of exosome-loaded Dex therapy holds potential as a promising and clinically relevant approach for injured spinal cord repair. However, further extensive research is warranted in this domain to validate and substantiate the outcomes presented in this study.

Building a pathway to recovery: Targeting ECM remodeling in CNS injuries

Extracellular matrix (ECM) is a complex and dynamic network of proteoglycans, proteins, and other macromolecules that surrounds cells in tissues. The ECM provides structural support to cells and plays a critical role in regulating various cellular functions. ECM remodeling is a dynamic process involving the breakdown and reconstruction of the ECM. This process occurs naturally during tissue growth, wound healing, and tissue repair. However, in the context of central nervous system (CNS) injuries, dysregulated ECM remodeling can lead to the formation of fibrotic and glial scars. CNS injuries encompass various traumatic events, including concussions and fractures. Following CNS trauma, the formation of glial and fibrotic scars becomes prominent. Glial scars primarily consist of reactive astrocytes, while fibrotic scars are characterized by an abundance of ECM proteins. ECM remodeling plays a pivotal and tightly regulated role in the development of these scars after spinal cord and brain injuries. Various factors like ECM components, ECM remodeling enzymes, cell surface receptors of ECM molecules, and downstream pathways of ECM molecules are responsible for the remodeling of the ECM. The aim of this review article is to explore the changes in ECM during normal physiological conditions and following CNS injuries. Additionally, we discuss various approaches that target various factors responsible for ECM remodeling, with a focus on promoting axon regeneration and functional recovery after CNS injuries. By targeting ECM remodeling, it may be possible to enhance axonal regeneration and facilitate functional recovery after CNS injuries.

Rodent Models of Spinal Cord Injury: From Pathology to Application

Spinal cord injury (SCI) often has devastating consequences for the patient's physical, mental and occupational health. At present, there is no effective treatment for SCI, and appropriate animal models are very important for studying the pathological manifestations, injury mechanisms, and corresponding treatment. However, the pathological changes in each injury model are different, which creates difficulties in selecting appropriate models for different research purposes. In this article, we analyze various SCI models and introduce their pathological features, including inflammation, glial scar formation, axon regeneration, ischemia-reperfusion injury, and oxidative stress, and evaluate the advantages and disadvantages of each model, which is convenient for selecting suitable models for different injury mechanisms to study therapeutic methods.

Cold stimuli, hot topic: An updated review on the biological activity of menthol in relation to inflammation

BACKGROUND

Rising incidence of inflammation-related diseases is an increasing concern nowadays. However, while menthol is a wildly-used and efficacious complementary medicine, its pharmacological mechanism still remains uncertain. Superimposed upon that, the aim of this review is to summarize the contemporary evidence of menthol's anti-inflammatory activity.

METHODS

Using the pharmacopeias and electronic databases, including Web of Science, PubMed, and CNKI, this study analyzed the relevant research articles and review articles from 2002 to 2022 and concluded those results and conjectures to finish this article.

RESULTS

The decrease in pro-inflammatory cytokines and related inflammatory markers, as well as associated pathway activation, was found to play the greatest role in the protective effects of menthol against inflammatory damage or association with protection against chronic inflammation.

CONCLUSION

This review mainly concludes the progress in menthol's anti-inflammatory activity. Further studies are needed to establish relationships between the mechanisms of action and to clarify the clinical relevance of any anti-inflammatory effects.

Rho/ROCK Pathway and Noncoding RNAs: Implications in Ischemic Stroke and Spinal Cord Injury

Ischemic strokes (IS) and spinal cord injuries (SCI) are major causes of disability. RhoA is a small GTPase protein that activates a downstream effector, ROCK. The up-regulation of the RhoA/ROCK pathway contributes to neuronal apoptosis, neuroinflammation, blood-brain barrier dysfunction, astrogliosis, and axon growth inhibition in IS and SCI. Noncoding RNAs (ncRNAs), such as microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), were previously considered to be non-functional. However, they have attracted much attention because they play an essential role in regulating gene expression in physiological and pathological conditions. There is growing evidence that ROCK inhibitors, such as fasudil and VX-210, can reduce injury in IS and SCI in animal models and clinical trials. Recently, it has been reported that miRNAs are decreased in IS and SCI, while lncRNAs are increased. Inhibiting the Rho/ROCK pathway with miRNAs alleviates apoptosis, neuroinflammation, oxidative stress, and axon growth inhibition in IS and SCI. Further studies are required to explore the significance of ncRNAs in IS and SCI and to establish new strategies for preventing and treating these devastating diseases.

Bazedoxifene, a Selective Estrogen Receptor Modulator, Promotes Functional Recovery in a Spinal Cord Injury Rat Model

In research on various central nervous system injuries, bazedoxifene acetate (BZA) has shown two main effects: neuroprotection by suppressing the inflammatory response and remyelination by enhancing oligodendrocyte precursor cell differentiation and oligodendrocyte proliferation. We examined the effects of BZA in a rat spinal cord injury (SCI) model. Anti-inflammatory and anti-apoptotic effects were investigated in RAW 264.7 cells, and blood-spinal cord barrier (BSCB) permeability and angiogenesis were evaluated in a human brain endothelial cell line (hCMEC/D3). In vivo experiments were carried out on female Sprague Dawley rats subjected to moderate static compression SCI. The rats were intraperitoneally injected with either vehicle or BZA (1mg/kg pre-SCI and 3 mg/kg for 7 days post-SCI) daily. BZA decreased the lipopolysaccharide-induced production of proinflammatory cytokines and nitric oxide in RAW 264.7 cells and preserved BSCB disruption in hCMEC/D3 cells. In the rats, BZA reduced caspase-3 activity at 1 day post-injury (dpi) and suppressed phosphorylation of MAPK (p38 and ERK) at dpi 2, hence reducing the expression of IL-6, a proinflammatory cytokine. BZA also led to remyelination at dpi 20. BZA contributed to improvements in locomotor recovery after compressive SCI. This evidence suggests that BZA may have therapeutic potential to promote neuroprotection, remyelination, and functional outcomes following SCI.

The adenosine A2A receptor alleviates postoperative delirium-like behaviors by restoring blood cerebrospinal barrier permeability in rats

Postoperative delirium (POD) is a common post-operative complication in elderly patients that is associated with increased morbidity and mortality. However, the neuropathogenesis of this complication remains unknown. The blood-cerebrospinal fluid barrier (BCB) and brain-blood barrier (BBB) are composed of tight junctions between cells that form physical barriers, and BBB damage plays an important role in the neuropathogenesis of POD. Nevertheless, the role of BCB in POD remains to be elucidated. Herein, we investigated the effect of adenosine A_2A receptor (A_2A R), a key regulator of the permeability of barriers, on surgery-induced increased permeability of BCB and POD-like behaviors. Open field, buried food, and Y maze tests were used to evaluate behavioral changes in rats after surgery. Levels of tight junction proteins, adherens junction proteins, A_2A R, GTP-RhoA, and ROCK2 in the choroid plexus were assessed by western blotting. The concentrations of NaFI and FITC-dextran in the cerebrospinal fluid (CSF) were detected by fluorescence spectrophotometry. Transmission electron microscopy was applied to observe the ultrastructure of the choroid plexus. Surgery/anesthesia decreased the levels of tight junction (e.g., ZO-1, occludin, and claudin1) proteins, increased concentrations of NaFI and FITC-dextran in CSF, damaged the ultrastructure of choroid plexus, and induced POD-like behaviors in rats. An A_2A R antagonist alleviated POD-like behaviors in rats. Furthermore, the A_2A R antagonist increased the levels of tight junction proteins and restored the permeability of BCB in rats with POD. Fasudil, a selective Rho-associated protein kinase 2 (ROCK2) inhibitor, ameliorated POD-like behaviors induced by A_2A R activation. Moreover, fasudil also abolished the increased levels of GTP-RhoA/ROCK2, decreased levels of tight junction proteins, and increased permeability of BCB caused by A_2A R activation. Our findings demonstrate that A_2A R might participate in regulating BCB permeability in rats with POD via the RhoA/ROCK2 signaling pathway, which suggests the potential of A_2A R as a therapeutic target for POD.

Strategies to neutralize RhoA/ROCK pathway after spinal cord injury

Regeneration is bungled following CNS injuries, including spinal cord injury (SCI). Inherent decay of permissive conditions restricts the regrowth of the mature CNS after an injury. Hypertrophic scarring, insignificant intrinsic axon-growth activity, and axon-growth inhibitory molecules such as myelin inhibitors and scar inhibitors constitute a significant hindrance to spinal cord repair. Besides these molecules, a combined absence of various mechanisms responsible for axonal regeneration is the main reason behind the dereliction of the adult CNS to regenerate. The neutralization of specific inhibitors/proteins by stymieing antibodies or encouraging enzymatic degradation results in improved axon regeneration. Previous efforts to induce regeneration after SCI have stimulated axonal development in or near lesion sites, but not beyond them. Several pathways are responsible for the axonal growth obstruction after a CNS injury, including SCI. Herein, we summarize the axonal, glial, and intrinsic factor which impedes the regeneration. We have also discussed the methods to stabilize microtubules and through this to maintain the proper cytoskeletal dynamics of growth cone as disorganized microtubules lead to the failure of axonal regeneration. Moreover, we primarily focus on diverse inhibitors of axonal growth and molecular approaches to counteract them and their downstream intracellular signaling through the RhoA/ROCK pathway.