Allicin protects traumatic spinal cord injury through regulating the HSP70/Akt/iNOS pathway in mice

[Exosomes from ectoderm mesenchymal stem cells inhibits lipopolysaccharide-induced microglial M1 polarization and promotes survival of H2O2-exposed PC12 cells by suppressing inflammatory response and oxidative stress]

OBJECTIVE

To investigate the potential value of exosomes derived from rat ectoderm mesenchymal stem cells (EMSCs-exo) for repairing secondary spinal cord injury.

METHODS

EMSCs-exo were obtained using ultracentrifugation from EMSCs isolated from rat nasal mucosa, identified by transmission electron microscope, nanoparticle tracking analysis (NTA), and Western blotting, and quantified using the BCA method. Neonatal rat microglia purified by differential attachment were induced with 100 μg/L lipopolysaccharide (LPS) and treated with 37.5 or 75 mg/L EMSCs-exo. PC12 cells were exposed to 400 μmol/L H2O2 and treated with EMSCs-exo at 37.5 or 75 mg/L. The protein and mRNA expressions of Arg1 and iNOS in the treated cells were determined with Western blotting and qRT- PCR, and the concentrations of IL- 6, IL-10, and IGF-1 in the supernatants were measured with ELISA. The viability and apoptosis of PC12 cells were detected using CCK-8 assay and flow cytometry.

RESULTS

The isolated rat EMSCs showed high expressions of nestin, CD44, CD105, and vimentin. The obtained EMSCs-exo had a typical cup-shaped structure under transmission electron microscope with an average particle size of 142 nm and positivity for CD63, CD81, and TSG101 but not vimentin. In LPS-treated microglia, EMSCs-exo treatment at 75 mg/L significantly increased Arg1 protein level and lowered iNOS protein expression (P < 0.05). EMSCs-exo treatment at 75 mg/L, as compared with the lower concentration at 37.5 mg/L, more strongly increased Arg1 mRNA expression and IGF-1 and IL-10 production and decreased iNOS mRNA expression and IL-6 production in LPS-induced microglia, and more effectively promoted cell survival and decreased apoptosis rate of H2O2-induced PC12 cells (P < 0.05).

CONCLUSION

EMSCs-exo at 75 mg/L can effectively reduce the proportion of M1 microglia and alleviate neuronal apoptosis under oxidative stress to promote neuronal survival, suggesting its potential in controlling secondary spinal cord injury.

The Proteostasis Network: A Global Therapeutic Target for Neuroprotection after Spinal Cord Injury

Proteostasis (protein homeostasis) is critical for cellular as well as organismal survival. It is strictly regulated by multiple conserved pathways including the ubiquitin-proteasome system, autophagy, the heat shock response, the integrated stress response, and the unfolded protein response. These overlapping proteostasis maintenance modules respond to various forms of cellular stress as well as organismal injury. While proteostasis restoration and ultimately organism survival is the main evolutionary driver of such a regulation, unresolved disruption of proteostasis may engage pro-apoptotic mediators of those pathways to eliminate defective cells. In this review, we discuss proteostasis contributions to the pathogenesis of traumatic spinal cord injury (SCI). Most published reports focused on the role of proteostasis networks in acute/sub-acute tissue damage post-SCI. Those reports reveal a complex picture with cell type- and/or proteostasis mediator-specific effects on loss of neurons and/or glia that often translate into the corresponding modulation of functional recovery. Effects of proteostasis networks on such phenomena as neuro-repair, post-injury plasticity, as well as systemic manifestations of SCI including dysregulation of the immune system, metabolism or cardiovascular function are currently understudied. However, as potential interventions that target the proteostasis networks are expected to impact many cell types across multiple organ systems that are compromised after SCI, such therapies could produce beneficial effects across the wide spectrum of highly variable human SCI.

Application of natural antioxidants from traditional Chinese medicine in the treatment of spinal cord injury

Spinal cord injury (SCI) is a devastating central nervous system disease, caused by physical traumas. With the characteristic of high disability rate, catastrophic dysfunction, and enormous burden on the patient’s family, SCI has become a tough neurological problem without efficient treatments. Contemporarily, the pathophysiology of SCI comprises complicated and underlying mechanisms, in which oxidative stress (OS) may play a critical role in contributing to a cascade of secondary injuries. OS substantively leads to ion imbalance, lipid peroxidation, inflammatory cell infiltration, mitochondrial disorder, and neuronal dysfunction. Hence, seeking the therapeutic intervention of alleviating OS and appropriate antioxidants is an essential clinical strategy. Previous studies have reported that traditional Chinese medicine (TCM) has antioxidant, anti-inflammatory, antiapoptotic and neuroprotective effects on alleviating SCI. Notably, the antioxidant effects of some metabolites and compounds of TCM have obtained numerous verifications, suggesting a potential therapeutic strategy for SCI. This review aims at investigating the mechanisms of OS in SCI and highlighting some TCM with antioxidant capacity used in the treatment of SCI.

Inflammation: A Target for Treatment in Spinal Cord Injury

Spinal cord injury (SCI) is a significant cause of disability, and treatment alternatives that generate beneficial outcomes and have no side effects are urgently needed. SCI may be treatable if intervention is initiated promptly. Therefore, several treatment proposals are currently being evaluated. Inflammation is part of a complex physiological response to injury or harmful stimuli induced by mechanical, chemical, or immunological agents. Neuroinflammation is one of the principal secondary changes following SCI and plays a crucial role in modulating the pathological progression of acute and chronic SCI. This review describes the main inflammatory events occurring after SCI and discusses recently proposed potential treatments and therapeutic agents that regulate inflammation after insult in animal models.

Current studies and potential future research directions on biological effects and related mechanisms of allicin

Allicin, a thiosulfonate extract from freshly minced garlic, has been reported to have various biological effects on different organs and systems of animals and human. It can reduce oxidative stress, inhibit inflammatory response, resist pathogen infection and regulate intestinal flora. In addition, dozens of studies also demonstrated allicin could reduce blood glucose level, protect cardiovascular system and nervous system, and fight against cancers. Allicin was widely used in disease prevention and health care. However, more investigations on human cohort study are needed to verify the biological or clinical effects of allicin in the future. In this review, we summarized the biological effects of allicin from previous outstanding and valuable studies and provided useful information for future studies on the health effects of allicin.

Allicin, an Antioxidant and Neuroprotective Agent, Ameliorates Cognitive Impairment

Allicin (diallylthiosulfinate) is a defense molecule produced by cellular contents of garlic (Allium sativum L.). On tissue damage, the non-proteinogenic amino acid alliin (S-allylcysteine sulfoxide) is converted to allicin in an enzyme-mediated process catalysed by alliinase. Allicin is hydrophobic in nature, can efficiently cross the cellular membranes and behaves as a reactive sulfur species (RSS) inside the cells. It is physiologically active molecule with the ability to oxidise the thiol groups of glutathione and between cysteine residues in proteins. Allicin has shown anticancer, antimicrobial, antioxidant properties and also serves as an efficient therapeutic agent against cardiovascular diseases. In this context, the present review describes allicin as an antioxidant, and neuroprotective molecule that can ameliorate the cognitive abilities in case of neurodegenerative and neuropsychological disorders. As an antioxidant, allicin fights the reactive oxygen species (ROS) by downregulation of NOX (NADPH oxidizing) enzymes, it can directly interact to reduce the cellular levels of different types of ROS produced by a variety of peroxidases. Most of the neuroprotective actions of allicin are mediated via redox-dependent pathways. Allicin inhibits neuroinflammation by suppressing the ROS production, inhibition of TLR4/MyD88/NF-κB, P38 and JNK pathways. As an inhibitor of cholinesterase and (AChE) and butyrylcholinesterase (BuChE) it can be applied to manage the Alzheimer's disease, helps to maintain the balance of neurotransmitters in case of autism spectrum disorder (ASD) and attention deficit hyperactive syndrome (ADHD). In case of acute traumatic spinal cord injury (SCI) allicin protects neuron damage by regulating inflammation, apoptosis and promoting the expression levels of Nrf2 (nuclear factor erythroid 2-related factor 2). Metal induced neurodegeneration can also be attenuated and cognitive abilities of patients suffering from neurological diseases can be ameliorates by allicin administration.

Neuroinflammation and Modulation Role of Natural Products After Spinal Cord Injury

Spinal cord injury (SCI) is a severe traumatic injury of the central nervous system, characterized by neurological dysfunction and locomotor disability. Although the underlying pathological mechanism of SCI is complex and remains unclear, the important role of neuroinflammation has been gradually unveiled in recent years. The inflammation process after SCI involves disruption of the blood–spinal cord barrier (BSCB), activation of gliocytes, infiltration of peripheral macrophages, and feedback loops between different cells. Thus, our first aim is to illustrate pathogenesis, related cells and factors of neuroinflammation after SCI in this review. Due to the good bioactivity of natural products derived from plants and medicinal herbs, these widely exist as food, health-care products and drugs in our lives. In the inflammation after SCI, multiple natural products exert satisfactory effects. Therefore, the second aim of this review is to sum up the effects and mechanisms of 25 natural compounds and 7 extracts derived from plants or medicinal herbs on neuroinflammation after SCI. Clarification of the SCI inflammation mechanism and a summary of the related natural products is helpful for in-depth research and drug development.

Allicin Alleviates Lead-Induced Bone Loss by Preventing Oxidative Stress and Osteoclastogenesis Via SIRT1/FOXO1 Pathway in Mice

The aim of this study was to investigate the effects of allicin on lead-induced bone loss in mice. Male C57BL/6 J mice (3-weeks-old) were randomly divided into four groups: control group, lead group, allicin+lead group, and allicin group. Micro-CT, histology, oxidative stress, and osteoclastogenesis-related gene expression were analyzed. The results showed that allicin significantly ameliorated lead-induced bone loss, reduced oxidative stress, and inhibited osteoclastogenesis in mice. Moreover, we found that allicin upregulated the expression of SIRT1 and deacetylation of FoxO1. In conclusion, our study demonstrated that allicin exerts protective effects on lead-induced bone loss via antioxidant activity, preventing osteoclastogenesis, and activating SIRT1/FOXO1 pathway in mice, implying a potential therapy for lead-induced bone loss.

Nutrition, Bioenergetics, and Metabolic Syndrome

According to the World Health Organization (WHO), the global nutrition report shows that whilst part of the world's population starves, the other part suffers from obesity and associated complications. A balanced diet counterparts these extreme conditions with the proper proportion, composition, quantity, and presence of macronutrients, micronutrients, and bioactive compounds. However, little is known on the way these components exert any influence on our health. These nutrients aiming to feed our bodies, our tissues, and our cells, first need to reach mitochondria, where they are decomposed into CO2 and H2O to obtain energy. Mitochondria are the powerhouse of the cell and mainly responsible for nutrients metabolism, but they are also the main source of oxidative stress and cell death by apoptosis. Unappropriated nutrients may support mitochondrial to become the Trojan horse in the cell. This review aims to provide an approach to the role that some nutrients exert on mitochondria as a major contributor to high prevalent Western conditions including metabolic syndrome (MetS), a constellation of pathologic conditions which promotes type II diabetes and cardiovascular risk. Clinical and experimental data extracted from in vitro animal and cell models further demonstrated in patients, support the idea that a balanced diet, in a healthy lifestyle context, promotes proper bioenergetic and mitochondrial function, becoming the best medicine to prevent the onset and progression of MetS. Any advance in the prevention and management of these prevalent complications help to face these challenging global health problems, by ameliorating the quality of life of patients and reducing the associated sociosanitary burden.

Protective Effects of Allicin on ISO-Induced Rat Model of Myocardial Infarction via JNK Signaling Pathway

OBJECTIVE

This research was aimed to explore protective effects of allicin on rat model of myocardial infarction via JNK signaling pathway.

METHODS

Rat myocardial ischemia model was established with subcutaneous injection of isoproterenol (ISO). Seventy-five rats were randomly divided into 5 groups (n = 15): sham group, ISO group, low-dose group (1.2 mg/kg/days for 7 days), medium-dose group (1.8 mg/kg/days for 7 days), and high-dose group (3.6 mg/kg/days for 7 days). Routine HE staining and Masson staining were performed to observe myocardial histopathology. The expression of oxidative stress-related indicators, heart tissue apoptosis-related proteins, and JNK and p-JNK proteins were measured for different groups.

RESULTS

Compared with the sham group, the T wave value of the ISO group was significantly increased (p < 0.01). When allicin was administered, the T wave values at different time points in all groups were all decreased. Compared with the sham group, the ratio of eNOS, Bcl-2/Bax was significantly decreased, and p-eNOS, iNOS, caspase-3, caspase-9, and Cyt-c were significantly elevated in the ISO group (p < 0.05). After allicin was administered, significant changes in these proteins were observed in the medium- and high-dose groups. There was no significant change in the expression of JNK protein in the ISO group compared with the sham group; however, the expression of eNOS and p-JNK protein were significantly upregulated (p < 0.01) and the expression of p-eNOS and iNOS were significantly downregulated (p < 0.01). When allicin was administered, expression of p-JNK protein was significantly downregulated.

CONCLUSION

Allicin can reduce oxidative stress damage and cardiomyocyte apoptosis in rat model of myocardial infarction and can significantly regulate JNK signaling pathway.

Targeting apoptosis and autophagy following spinal cord injury: Therapeutic approaches to polyphenols and candidate phytochemicals

Spinal cord injury (SCI) is a neurological disorder associated with the loss of sensory and motor function. Understanding the precise dysregulated signaling pathways, especially apoptosis and autophagy following SCI, is of vital importance in developing innovative therapeutic targets and treatments. The present study lies in the fact that it reveals the precise dysregulated signaling mediators of apoptotic and autophagic pathways following SCI and also examines the effects of polyphenols and other candidate phytochemicals. It provides new insights to develop new treatments for post-SCI complications. Accordingly, a comprehensive review was conducted using electronic databases including, Scopus, Web of Science, PubMed, and Medline, along with the authors' expertise in apoptosis and autophagy as well as their knowledge about the effects of polyphenols and other phytochemicals on SCI pathogenesis. The primary mechanical injury to spinal cord is followed by a secondary cascade of apoptosis and autophagy that play critical roles during SCI. In terms of pharmacological mechanisms, caspases, Bax/Bcl-2, TNF-α, and JAK/STAT in apoptosis along with LC3 and Beclin-1 in autophagy have shown a close interconnection with the inflammatory pathways mainly glutamatergic, PI3K/Akt/mTOR, ERK/MAPK, and other cross-linked mediators. Besides, apoptotic pathways have been shown to regulate autophagy mediators and vice versa. Prevailing evidence has highlighted the importance of modulating these signaling mediators/pathways by polyphenols and other candidate phytochemicals post-SCI. The present review provides dysregulated signaling mediators and therapeutic targets of apoptotic and autophagic pathways following SCI, focusing on the modulatory effects of polyphenols and other potential phytochemical candidates.

Allicin pharmacology: Common molecular mechanisms against neuroinflammation and cardiovascular diseases

According to investigations in phytomedicine and ethnopharmacology, the therapeutic properties of garlic (Allium sativum) have been described by ancestral cultures. Notwithstanding, it is of particular concern to elucidate the molecular mechanisms underlying this millenary empirical knowledge. Allicin (S-allyl prop-2-ene-1-sulfinothioate), a thioester of sulfenic acid, is one of the main bioactive compounds present in garlic, and it is responsible for the particular aroma of the spice. The pharmacological attributes of allicin integrate a broad spectrum of properties (e.g., anti-inflammatory, immunomodulatory, antibiotic, antifungal, antiparasitic, antioxidant, nephroprotective, neuroprotective, cardioprotective, and anti-tumoral activities, among others). The primary goal of the present article is to review and clarify the common molecular mechanisms by which allicin and its derivates molecules may perform its therapeutic effects on cardiovascular diseases and neuroinflammatory processes. The intricate interface connecting the cardiovascular and nervous systems suggests that the impairment of one organ could contribute to the dysfunction of the other. Allicin might target the cornerstone of the pathological processes underlying cardiovascular and neuroinflammatory disorders, like inflammation, renin-angiotensin-aldosterone system (RAAS) hyperactivation, oxidative stress, and mitochondrial dysfunction. Indeed, the current evidence suggests that allicin improves mitochondrial function by enhancing the expression of HSP70 and NRF2, decreasing RAAS activation, and promoting mitochondrial fusion processes. Finally, allicin represents an attractive therapeutic alternative targeting the complex interaction between cardiovascular and neuroinflammatory disorders.

The Importance of Natural Antioxidants in the Treatment of Spinal Cord Injury in Animal Models: An Overview

Patients with spinal cord injury (SCI) face devastating health, social, and financial consequences, as well as their families and caregivers. Reducing the levels of reactive oxygen species (ROS) and oxidative stress are essential strategies for SCI treatment. Some compounds from traditional medicine could be useful to decrease ROS generated after SCI. This review is aimed at highlighting the importance of some natural compounds with antioxidant capacity used in traditional medicine to treat traumatic SCI. An electronic search of published articles describing animal models of SCI treated with natural compounds from traditional medicine was conducted using the following terms: Spinal Cord Injuries (MeSH terms) AND Models, Animal (MeSH terms) AND [Reactive Oxygen Species (MeSH terms) AND/OR Oxidative Stress (MeSH term)] AND Medicine, Traditional (MeSH terms). Articles reported from 2010 to 2018 were included. The results were further screened by title and abstract for studies performed in rats, mice, and nonhuman primates. The effects of these natural compounds are discussed, including their antioxidant, anti-inflammatory, and antiapoptotic properties. Moreover, the antioxidant properties of natural compounds were emphasized since oxidative stress has a fundamental role in the generation and progression of several pathologies of the nervous system. The use of these compounds diminishes toxic effects due to their high antioxidant capacity. These compounds have been tested in animal models with promising results; however, no clinical studies have been conducted in humans. Further research of these natural compounds is crucial to a better understanding of their effects in patients with SCI.

Trehalose protects against spinal cord injury through regulating heat shock proteins 27 and 70 and caspase-3 genes expression

Background Heat shock proteins (HSPs) are a class of highly conserved proteins responsible for various functions critical to cell survival. Pharmacological induction of HSPs has been implicated in the regulation of neuronal loss and functional deficits in peripheral and central nervous system injuries. Accordingly, the present study was conducted to investigate the effect of trehalose on spinal expression of HSP27, HSP70 and caspase-3 genes following traumatic spinal cord injury (SCI) in rats. Methods Male rats weighing 250-300 g underwent laminectomy and were divided into four groups including sham, SCI (received SCI), vehicle (received SCI and phosphate buffer saline intrathecally) and trehalose (received 10 mM trehalose intrathecally following SCI). On days 1, 3 and 7 after injury, HSP27, HSP70 and caspase-3 genes transcripts were quantified in spinal cord tissues via a real-time PCR technique. In addition, locomotor function was assessed using the Basso, Beattie and Bresnahan (BBB) rating scale. Results SCI induced the expression of HSP27, HSP70 and caspase-3 genes and BBB score at all time points. Trehalose treatment upregulated HSP27, HSP70 genes expression at 1 day after SCI. Interestingly, a significant reduction in the expression of HSP27 and HSP70 genes was observed on days 3 and 7 following trauma compared with the vehicle group (p < 0.01). Caspase-3 gene showed a decrease in expression in the trehalose-treated group at all times. In addition, neurological function revealed an improvement after treatment with trehalose. Conclusion This study suggests that the neuroprotective effect of trehalose is mediated via regulation of HSP27 and HSP70, which are involved in cytoprotection and functional recovery following SCI.

Neuroprotective role of icariin in experimental spinal cord injury via its antioxidant, anti‑neuroinflammatory and anti‑apoptotic properties

Icariin is a type of flavonoid derived from the Chinese herbal plant Epimedium sagittatum Maxim. Mounting evidence has confirmed the beneficial effects of icariin in neurological diseases, including spinal cord injury (SCI). The aim of the present study was to investigate the neuroprotective effects of icariin in SCI and the precise underlying mechanism. The weight‑drop injury technique was applied to construct an SCI model in Sprague‑Dawley rats. Icariin (35 µmol/kg) was administered orally once daily for 7 consecutive days to examine its neuroprotective effects. The Basso, Beattie and Bresnahan scoring system was used for neurobehavioral evaluation. The water content of the injured spinal cord was measured via the dry‑wet weight method. Biochemical indices were examined by colorimetric assay using commercially available kits. Western blot analysis was used to detect protein expression. Icariin significantly accelerated the recovery of the locomotor function of SCI rats and decreased spinal cord water content. Icariin also attenuated SCI‑induced pro‑apoptotic protein expression and activity, while it increased anti‑apoptotic protein levels. In addition, icariin alleviated oxidative stress in SCI rats and decreased the levels of inflammatory molecules, including interleukin (IL)‑1β, IL‑6, tumor necrosis factor‑α, nitric oxide, nuclear factor‑κB and inducible nitric oxide synthase, and increased the expression of anti‑inflammatory proteins, including NADPH‑quinone oxidoreductase‑1, heme oxygenase‑1 and nuclear factor erythroid 2‑related factor 2 in the injured spinal cord. Therefore, icariin treatment accelerated locomotor function recovery in SCI, and its protective effects may be mediated via its antioxidant, anti‑inflammatory and anti‑apoptotic bioactivity.

Upregulation of miR‑33b promotes endometriosis via inhibition of Wnt/β‑catenin signaling and ZEB1 expression

The present study aimed to investigate the role and mechanisms of microRNA (miR)‑33b in endometriosis (Ems). Reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR), MTT assays, flow cytometry, caspase‑3/9 activity assays and western blotting were performed in the present study. Initially, miR‑33b expression in an Ems rat model was investigated by RT‑qPCR and was demonstrated to be upregulated in Ems tissue samples of rats compared with the control group. In addition, miR‑33b upregulation inhibited cell growth and enhanced apoptosis in an Ems model (primary cell cultures) compared with the control group. In addition, miR‑33b up‑regulation reduced Wnt/β‑catenin signaling pathway and suppressed zinc finger E‑box‑binding homeobox 1 (ZEB1) protein expression in the in vitro Ems model (primary cell cultures) compared with the control group. Furthermore, small interfering‑ZEB1 ameliorated the effects of miR‑33b downregulation on Ems cell growth in the in vitro Ems model. Additionally, a Wnt agonist reduced the effects of miR‑33b upregulation on Ems cell growth in the in vitro Ems model. In conclusion, the present study demonstrated that upregulation of miR‑33b may promote Ems through Wnt/β‑catenin by ZEB1 expression.

Dietary Nutrients and Bioactive Substances Modulate Heat Shock Protein (HSP) Expression: A Review

Interest in the heat shock proteins (HSPs), as a natural physiological toolkit of living organisms, has ranged from their chaperone function in nascent proteins to the remedial role following cell stress. As part of the defence system, HSPs guarantee cell tolerance against a variety of stressors, including exercise, oxidative stress, hyper and hypothermia, hyper and hypoxia and improper diets. For the past couple of decades, research on functional foods has revealed a number of substances likely to trigger cell protection through mechanisms that involve the induction of HSP expression. This review will summarize the occurrence of the most easily inducible HSPs and describe the effects of dietary proteins, peptides, amino acids, probiotics, high-fat diets and other food-derived substances reported to induce HSP response in animals and humans studies. Future research may clarify the mechanisms and explore the usefulness of this natural alternative of defense and the modulating mechanism of each substance.

Allicin activates autophagic cell death to alleviate the malignant development of thyroid cancer

Allicin has been reported to inhibit cancer cell proliferation, induce cell apoptosis and enhance the accumulation of reactive oxygen species. However, it has remained elusive whether allicin improves multidrug resistance in thyroid cancer cells through modulating autophagy. The present study demonstrated that combined use of allicin and cisplatin or carboplatin resulted in an enhanced growth inhibitory effect on SW1736 and HTh-7 cells. Furthermore, treatment with allicin significantly increased SW1736 and HTh-7 cell autophagy. Of note, allicin-induced cell death was largely abolished by 3-methyladenine or chloroquine treatment, suggesting that allicin-induced A549 cell death was dependent on autophagy. Western blot analysis demonstrated that allicin treatment inhibited the activation of Akt, mammalian target of rapamycin and S6. Furthermore, it was demonstrated that combined use of allicin and rapamycin induced more cell death compared with that induced by allicin or rapamycin alone. In conclusion, allicin may serve as an adjunctive therapy for thyroid cancer, as it induces autophagy-dependent cell death even when cancer cells have developed apoptosis resistance.

Downregulating PI3K/Akt/NF-κB signaling with allicin for ameliorating the progression of osteoarthritis:in vitroandvivostudies

A schematic illustration of the potential protective effects of allicin on osteoarthritis development.

Hormonal therapy in traumatic spinal cord injury

Traumatic spinal cord injuries are major health problems and the underlying pathophysiological events and treatment strategies are currently under investigation. In this article, we critically reviewed the literature investigating the effects of estrogen, progesterone, and human chorionic gonadotropin on spinal cord damage or preservation following traumatic spinal cord injury. The National Library of Medicine database was searched through December 2016 using PubMed for articles addressing the clinical relevance of the hormones to improve neural structural integrity following traumatic spinal cord injury. It was found that each of these hormones, through varied mechanisms, could serve to reduce the harmful effects associated with spinal cord injury, and could aid in restoring some function to the injured spinal cord in the animal models. The most striking effects were seen in the reduction of inflammation commonly linked to injury of the central nervous system. The effects of human chorionic gonadotropin administration following spinal cord injury have received far less attention than those of either estrogen or progesterone, and additional inquiry could be of general benefit. In this article, we discussed the outstanding questions and suggested future directions for further investigation.