Ginsenoside Rb1 inhibits neuronal apoptosis and damage, enhances spinal aquaporin 4 expression and improves neurological deficits in rats with spinal cord ischemia-reperfusion injury

Ginsenoside Rb1 in cardiovascular and cerebrovascular diseases: A review of therapeutic potentials and molecular mechanisms

Cardiovascular and cerebrovascular diseases (CCVDs), which are circulatory system diseases caused by heart defects and vascular diseases, are the major noncommunicable diseases affecting global public health. With the improvement of economic level and the change of human lifestyle, the prevalence of CCVDs continues to increase. Ginseng (Panax ginseng C. A. Mey.) was widely used in traditional diseases due to its supposed tonic properties. Ginsenoside Rb1 (G-Rb1) is the most abundant active ingredient with multiple pharmacological effects extracted from ginseng, which has been shown to have potential benefits on the cardiovascular system through a variety of mechanisms, including anti-oxidation, anti-inflammatory, regulation of vasodilation, reduction of platelet adhesion, influence of calcium ion channels, improvement of lipid distribution, involving in glucose metabolism and controlling blood sugar. This review reviewed the protective effects of G-Rb1 on CCVDs and its potential mechanisms, such as atherosclerosis (AS), hypertension, coronary heart disease (CHD), ischemic stroke (IS) and periocular microvascular retinopathy. Finally, we reviewed and reported the results of in vivo and in vitro experiments using G-Rb1 to improve CCVDs, highlighted its efficacy, safety, and limitations.

Progress of Ginsenoside Rb1 in neurological disorders

Ginseng is frequently used in traditional Chinese medicine to treat neurological disorders. The primary active component of ginseng is ginsenoside, which has been classified into more than 110 types based on their chemical structures. Ginsenoside Rb1 (GsRb1)-a protopanaxadiol saponin and a typical ginseng component-exhibits anti-inflammatory, anti-oxidant, anti-apoptotic, and anti-autophagy properties in the nervous system. Neurological disorders remain a leading cause of death and disability globally. GsRb1 effectively treats neurological disorders. To contribute novel insights to the understanding and treatment of neurological disorders, we present a comprehensive review of the pharmacokinetics, actions, mechanisms, and research development of GsRb1 in neurological disorders.

Mechanisms of ginsenosides exert neuroprotective effects on spinal cord injury: A promising traditional Chinese medicine

Spinal cord injury (SCI) is a devastating disorder of the central nervous system (CNS). It is mainly caused by trauma and reduces the quality of life of the affected individual. Ginsenosides are safe and effective traditional Chinese medicines (TCMs), and their efficacy against SCI is being increasingly researched in many countries, especially in China and Korea. This systematic review evaluated the neuroprotective effects of ginsenosides in SCI and elucidated their properties.

The Water Transport System in Astrocytes–Aquaporins

Highlights

(AQPs) are transmembrane proteins responsible for fast water movement across cell membranes, including those of astrocytes.

The expression and subcellular localization of AQPs in astrocytes are highly dynamic under physiological and pathological conditions.

Besides their primary function in water homeostasis, AQPs participate in many ancillary functions including glutamate clearance in tripartite synapses and cell migration.

Abstract

Astrocytes have distinctive morphological and functional characteristics, and are found throughout the central nervous system. Astrocytes are now known to be far more than just housekeeping cells in the brain. Their functions include contributing to the formation of the blood–brain barrier, physically and metabolically supporting and communicating with neurons, regulating the formation and functions of synapses, and maintaining water homeostasis and the microenvironment in the brain. Aquaporins (AQPs) are transmembrane proteins responsible for fast water movement across cell membranes. Various subtypes of AQPs (AQP1, AQP3, AQP4, AQP5, AQP8 and AQP9) have been reported to be expressed in astrocytes, and the expressions and subcellular localizations of AQPs in astrocytes are highly correlated with both their physiological and pathophysiological functions. This review describes and summarizes the recent advances in our understanding of astrocytes and AQPs in regard to controlling water homeostasis in the brain. Findings regarding the features of different AQP subtypes, such as their expression, subcellular localization, physiological functions, and the pathophysiological roles of astrocytes are presented, with brain edema and glioma serving as two representative AQP-associated pathological conditions. The aim is to provide a better insight into the elaborate “water distribution” system in cells, exemplified by astrocytes, under normal and pathological conditions.

The Role of Saponins in the Treatment of Neuropathic Pain

Neuropathic pain is a chronic pain caused by tissue injury or disease involving the somatosensory nervous system, which seriously affects the patient's body function and quality of life. At present, most clinical medications for the treatment of neuropathic pain, including antidepressants, antiepileptic drugs, or analgesics, often have limited efficacy and non-negligible side effects. As a bioactive and therapeutic component extracted from Chinese herbal medicine, the role of the effective compounds in the prevention and treatment of neuropathic pain have gradually become a research focus to explore new analgesics. Notably, saponins have shown analgesic effects in a large number of animal models. In this review, we summarized the most updated information of saponins, related to their analgesic effects in neuropathic pain, and the recent progress on the research of therapeutic targets and the potential mechanisms. Furthermore, we put up with some perspectives on future investigation to reveal the precise role of saponins in neuropathic pain.

Recent progress (2015-2020) in the investigation of the pharmacological effects and mechanisms of ginsenoside Rb1, a main active ingredient in Panax ginseng Meyer

Ginsenoside Rb1 (Rb1), one of the most important ingredients in Panax ginseng Meyer, has been confirmed to have favorable activities, including reducing antioxidative stress, inhibiting inflammation, regulating cell autophagy and apoptosis, affecting sugar and lipid metabolism, and regulating various cytokines. This study reviewed the recent progress on the pharmacological effects and mechanisms of Rb1 against cardiovascular and nervous system diseases, diabetes, and their complications, especially those related to neurodegenerative diseases, myocardial ischemia, hypoxia injury, and traumatic brain injury. This review retrieved articles from PubMed and Web of Science that were published from 2015 to 2020. The molecular targets or pathways of the effects of Rb1 on these diseases are referring to HMGB1, GLUT4, 11β-HSD1, ERK, Akt, Notch, NF-κB, MAPK, PPAR-γ, TGF-β1/Smad pathway, PI3K/mTOR pathway, Nrf2/HO-1 pathway, Nrf2/ARE pathway, and MAPK/NF-κB pathway. The potential effects of Rb1 and its possible mechanisms against diseases were further predicted via Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and disease ontology semantic and enrichment (DOSE) analyses with the reported targets. This study provides insights into the therapeutic effects of Rb1 and its mechanisms against diseases, which is expected to help in promoting the drug development of Rb1 and its clinical applications.

Decreased AQP4 Expression Aggravates ɑ-Synuclein Pathology in Parkinson's Disease Mice, Possibly via Impaired Glymphatic Clearance

The pathological hallmarks of Parkinson's disease (PD), a neurodegenerative disorder, are the selective loss of dopamine neurons in the substantia nigra pars compacta (SNpc) and the presence of α-synuclein (α-syn) aggregates in the form of Lewy bodies/Lewy neurites (LBs/LNs) in neurons. Recent studies have indicated that aquaporin 4 (AQP4), as a predominant water channel protein in the brain, is involved in the progression of Parkinson's disease (PD). However, it remains unclear whether AQP4 expression affects α-syn pathology in Parkinson's disease. In this study, we established a progressive PD model by subjecting AQP4 null (AQP4^+/-) mice to bilateral intrastriatal injection of α-syn preformed fibrils (PFFs) and investigated the effect of decreased AQP4 expression on the development of PD. We found that decreased expression of AQP4 accelerated pathologic deposition of α-syn and facilitated the loss of dopamine neurons and behavioral disorders. Draining of macromolecules from the brain via the glymphatic pathway was slowed due to decreased AQP4 expression. Taken together, these findings indicate that decreased AQP4 expression may aggravate PD-like pathology, possibly via impairment of the glymphatic pathway.

Ginsenoside Rb1 attenuates microglia activation to improve spinal cord injury via microRNA-130b-5p/TLR4/NF-κB axis

Ginsenoside Rb1 (GRb1), a major ingredient of ginseng, has been found to be a potential protective agent in spinal cord injury (SCI) and in activated microglia-induced neuronal injury. This study discovered that GRb1 could facilitate miR-130b-5p expression in SCI rats and Toll-like receptor 4 (TLR4; a crucial player in inflammation) was a potential target of miR-130b-5p. Hence, we further investigated whether GRb1 could relieve SCI by reducing microglia-mediated inflammatory responses and neuronal injury via miR-130b-5p/TLR4 pathways. The results showed that GRb1 alleviated SCI through inhibiting neuronal apoptosis and proinflammatory factor expression via increasing miR-130b-5p.GRb1 weakened the damage of activated microglia to neurons through upregulating miR-130b-5p. miR-130b-5p attenuated activated microglia-induced neuron injury via targeting TLR4. GRb1 inactivated TLR4/nuclear factor-κB (NF-κB) activation and inhibited proinflammatory cytokine secretion by increasing miR-130b-5p in activated microglia. As a conclusion, GRb1 alleviated SCI through reducing activated microglia-induced neuronal injury via miR-130b-5p/TLR4/NF-κB axis, providing a deep insight into the molecular basis of GRb1 in the treatment of SCI.

Ginsenoside Rb1 is an immune-stimulatory agent with antiviral activity against enterovirus 71

ETHNOPHARMACOLOGICAL RELEVANCE

According to the theory of traditional Chinese medicine, the main pathogenesis of severe hand, foot and mouth disease (HFMD) is that the heat and wet poisons are deeply trapped in the viscera, which causes the deficiency of Qi and Yin in the patient's body. Ginsenoside Rb1 (Rb1) is the most abundant triterpenoid saponin in Panax quinquefolius L., which has the function of Qi-invigorating and Yin-nourishing. Enterovirus 71 (EV71) is one of the causative pathogens of HFMD, especially the form associated with some lethal complications. Therefore, the therapeutic effect of Rb1 on this disease caused by EV71 infection is worth exploring.

AIM OF THE STUDY

We explored the effective antiviral activities of Rb1 against EV71 in vitro and in vivo and investigated its preliminary antiviral mechanisms.

MATERIAL AND METHODS

EV71-infected two-day-old suckling mice model was employed to detect the antiviral effects of Rb1 in vivo. To detect the antiviral effects of Rb1 in vitro, cytopathic effect (CPE) reduction assay was performed in EV71-infected Rhabdomyosarcoma (RD) cells. Interferon (IFN)-β interference experiment was employed to detect the antiviral mechanism of Rb1.

RESULTS

In this paper, we first found that Rb1 exhibited strong antiviral activities in EV71-infected suckling mice when compared to those of ribavirin. Administration of Rb1 reduced the CPE of EV71-infected RD cells in a dose-dependent manner. Moreover, EV71-induced viral protein-1 (VP-1) expression was significantly reduced by Rb1 administration in vitro and in vivo. Furthermore, Rb1 treatment could induce high cellular and humoral immune responses in vivo. Meanwhile, Rb1 contributed to the enhanced Type I IFN responses and IFN-β knockdown reversed the antiviral activity of Rb1 in vitro.

CONCLUSION

In summary, our findings suggest that Rb1 is an immune-stimulatory agent and provide an insight into therapeutic potentials of Rb1 for the treatment of EV71 infection.

The Role of Astrogliosis in Formation of the Syrinx in Spinal Cord Injury

A massive localized trauma to the spinal cord results in complex pathologic events driven by necrosis and vascular damage which in turn leads to hemorrhage and edema. Severe, destructive and very protracted inflammatory response is characterized by infiltration by phagocytic macrophages of a site of injury which is converted into a cavity of injury (COI) surrounded by astroglial reaction mounted by the spinal cord. The tissue response to the spinal cord injury (SCI) has been poorly understood but the final outcome appears to be a mature syrinx filled with the cerebrospinal fluid with related neural tissue loss and permanent neurologic deficits. This paper reviews known pathologic mechanisms involved in the formation of the COI after SCI and discusses the integrative role of reactive astrogliosis in mechanisms involved in the removal of edema after the injury. A large proportion of edema fluid originating from the trauma and then from vasogenic edema related to persistent severe inflammation, may be moved into the COI in an active process involving astrogliosis and specifically over-expressed aquaporins.

Total saponin extract, ginsenoside Rb1, and compound K alleviate peripheral and central neuropathic pain through estrogen receptors on rats

In this study, we investigated whether total saponin extract (TSE), ginsenoside Rb1, and Rb1 metabolite compound K, which are isolated from red ginseng, have antinociceptive effects on peripheral and central neuropathic pain (PNP and CNP, respectively). PNP and CNP were induced by tail nerve injury (TNI) at S1 and by contusive spinal cord injury (SCI) at T9 in male Sprague-Dawley rats, respectively. Two weeks after TNI or 4 weeks after SCI, pain-induced rats were orally administered vehicle, TSE (50 mg/kg), Rb1 (12.5 mg/kg), compound K (7 mg/kg), or gabapentin (GBP, 60 mg/kg), and the antinociceptive effects were examined by von Frey filament, cold/warm water, and hot plate analyses. Allodynia and hyperalgesia were significantly alleviated by TSE, Rb1, and GBP 1 hr after drug administration. The immunohistochemistry and real-time RT-PCR results showed that the activation of microglia/astrocytes and the expression of inflammatory mediators such as Il-1β, Il-6, iNOS, and Cox-2 were also significantly inhibited in L4-L5 spinal cord of CNP-induced rats 1 hr after drug administration. Furthermore, the antinociceptive effects of TSE and Rb1 were reversed by treatment with the estrogen receptor (ER) antagonist ICI182780. In particular, compound K also significantly alleviated both PNP and CNP. Therefore, our results indicate that TSE, Rb1, and compound K have potential antinociceptive effects against neuropathic pain that might be mediated through the ER.

Research progress in use of traditional Chinese medicine for treatment of spinal cord injury

BACKGROUND

Spinal cord injury (SCI) is a serious central nervous system disorder caused by trauma that has gradually become a major challenge in clinical medical research. As an important branch of worldwide medical research, traditional Chinese medicine (TCM) is rapidly moving towards a path of reform and innovation. Therefore, this paper systematically reviews research related to existing TCM treatments for SCI, with the aims of identifying deficits and shortcomings within the field, and proposing feasible alternative prospects.

METHODS

All data and conclusions in this paper were obtained from articles published by peers in relevant fields. PubMed, SciFinder, Google Scholar, Web of Science, and CNKI databases were searched for relevant articles. Results regarding TCM for SCI were identified and retrieved, then manually classified and selected for inclusion in this review.

RESULTS

The literature search identified a total of 652 articles regarding TCM for SCI. Twenty-eight treatments (16 active ingredients, nine herbs, and three compound prescriptions) were selected from these articles; the treatments have been used for the prevention and treatment of SCI. In general, these treatments involved antioxidative, anti-inflammatory, neuroprotective, and/or antiapoptotic effects of TCM compounds.

CONCLUSIONS

This paper showed that TCM treatments can serve as promising auxiliary therapies for functional recovery of patients with SCI. These findings will contribute to the development of diversified treatments for SCI.

Jingshu Keli and its Components Notoginsenoside R1 and Ginsenoside Rb1 Alleviate the Symptoms of Cervical Myelopathy through Kir3.1 Mediated Mechanisms

Background & Objective::

Cervical Spondylotic Myelopathy (CSM) is one of the most serious spinal cord disorders in adults. Pharmacological modulation of ion channels is a common strategy to interfere with CSM and prevent neuronal damage.

Methods:

Here, we investigated the effects of Jingshu Keli (JSKL), a traditional Chinese herbal formula, on CSM-related gait abnormality, mechanical allodynia and thermal hyperalgesia, and assessed the neuronal mechanisms of JSKL on cultured brainstem cells. Behavioral tests and patch clamp recordings were performed to make this assessment.

Results:

In our study, we found that JSKL significantly recovered the gait performance (P<0.001) and decreased the levels of mechanical pain in 18.9% (P<0.01) and thermal pain in 18.1% (P<0.05). Further investigation suggested that JSKL and its containing ginsenoside Rb1 (GRb1), notoginsenoside R1 (NGR1) reduced the action potential frequency in 38.5%, 27.2%, 25.9%, and hyperpolarized resting membrane potential in 15.0%, 13.8%, 12.1%, respectively. Kir channels, not KV channels and KCa channels, were the major intermediate factors achieving treatment effects. Finally, immunostaining results showed that the phosphorylation of Kir3.1 was promoted, whereas the total expression level did not change.

Conclusion:

Our study reveals a novel strategy of treating CSM by using Traditional Chinese Medicines (TCMs) containing active components.

Aquaporin 4 regulation by ginsenoside Rb1 intervenes with oxygen-glucose deprivation/reoxygenation-induced astrocyte injury

BACKGROUND

Spinal cord ischemia-reperfusion injury (SCII) is a common complication of spinal surgery as well as thoracic and abdominal surgery. Acute cytotoxic edema is the key pathogenic alteration. Therefore, avoiding or decreasing cellular edema has become the major target for SCII treatment.

METHODS

The antiedema activity of ginsenoside Rb1 on aquaporin (AQP) 4, nerve growth factor (NGF), and brain-derived neurotrophic factor expression was detected by western blot and real-time polymerase chain reaction under conditions of oxygen-glucose deprivation/reoxygenation (OGD/R) in a rat astrocyte model in vitro. In addition, the cellular membrane permeability of AQP4 overexpressing cells or AQP4 small interfering RNA-transfected cells was detected.

RESULTS

Ginsenoside Rb1 significantly prevented OGD/R-induced AQP4 downregulation in rat astrocytes. In addition, ginsenoside Rb1 treatment or AQP4 overexpression in rat astrocytes significantly attenuated the OGD/R-induced increase of cellular membrane permeability. Moreover, ginsenoside Rb1 obviously prevented the OGD/R-induced decrease of NGF and BDNT expression in rat astrocytes.

CONCLUSION

These findings demonstrate that ginsenoside Rb1 can relieve spinal cord edema and improve neurological function by increasing AQP4 expression.

Antinociceptive effects of Ginsenoside Rb1 in a rat model of cancer-induced bone pain

Ginsenoside Rb1 (GRb1) is a major ingredient of ginseng, a traditional medicine that has been used for thousands of years. Previous studies have reported that GRb1 had anti-inflammatory, antioxidant and neuroprotective effects. The current study aimed to evaluate the antinociceptive effects of GRb1 in a rat model of cancer-induced bone pain (CIBP) established by intratibial injection of Walker 256 cells. Intraperitoneal injection (i.p.) of GRb1 (5 and 10 mg/kg, but not 1 mg/kg) partially and transiently reversed the mechanical allodynia and thermal hyperalgesia in CIBP rats at 14 days following surgery when the pain behavior is established. Furthermore, repeated administration of GRb1 demonstrated persistent analgesic effect. Additionally, the protein expression and immunoreactivity of iba1, which is the maker of microglia, was significantly suppressed in CIBP rats treated with GRb1 (i.p., 10 mg/kg) from day 12 for three consecutive days compared with CIBP rats treated with a vehicle. Furthermore, upregulation of spinal interleukin (IL)-1β, IL-6 and tumor necrosis factor-α were also significantly inhibited by the treatment of GRb1 (i.p., 10 mg/kg) from day 12 for three consecutive days. Together, these results indicated that GRb1 may attenuate CIBP via inhibiting the activation of microglia and glial-derived proinflammatory cytokines.

Inhibition of Autophagy is Involved in the Protective Effects of Ginsenoside Rb1 on Spinal Cord Injury

Spinal cord injury (SCI) is a devastating neurological disorder. Autophagy is induced and plays a crucial role in SCI. Ginsenoside Rb1 (Rb1), one of the major active components extracted from Panax Ginseng CA Meyer, has exhibited neuroprotective effects in various neurodegenerative diseases. However, it remains unknown whether autophagy is involved in the neuroprotection of Rb1 on SCI. In this study, we examined the regulation of autophagy following Rb1 treatment and its involvement in the Rb1-induced neuroprotection in SCI and in vitro injury model. Firstly, we found that Rb1 treatment decreased the loss of motor neurons and promoted function recovery in the SCI model. Furthermore, we found that Rb1 treatment inhibited autophagy in neurons, and suppressed neuronal apoptosis and autophagic cell death in the SCI model. Finally, in the in vitro injury model, Rb1 treatment increased the viability of PC12 cells and suppressed apoptosis by inhibiting excessive autophagy, whereas stimulation of autophagy by rapamycin abolished the anti-apoptosis effect of Rb1. Taken together, these findings suggest that the inhibition of autophagy is involved in the neuroprotective effects of Rb1 on SCI.

Pretreatment with AQP4 and NKCC1 Inhibitors Concurrently Attenuated Spinal Cord Edema and Tissue Damage after Spinal Cord Injury in Rats

Spinal cord injury (SCI) affects more than 2.5 million people worldwide. Spinal cord edema plays critical roles in the pathological progression of SCI. This study aimed to delineate the roles of aquaporin 4 (AQP4) and Na⁺-K⁺-Cl⁻ cotransporter 1 (NKCC1) in acute phase edema and tissue destruction after SCI and to explore whether inhibiting both AQP4 and NKCC1 could improve SCI-induced spinal edema and damage. Rat SCI model was established by modified Allen's method. Spinal cord water content, cerebrospinal fluid lactose dehydrogenase (LDH) activity, AQP4 and NKCC1 expression, and spinal cord pathology from 30 min to 7 days after SCI were monitored. Additionally, aforementioned parameters in rats treated with AQP4 and/or NKCC1 inhibitors were assessed 2 days after SCI. Spinal cord water content was significantly increased 1 h after SCI while AQP4 and NKCC1 expression and spinal fluid LDH activity elevated 6 h after SCI. Spinal cord edema and spinal cord destruction peaked around 24 h after SCI and maintained at high levels thereafter. Treating rats with AQP4 inhibitor TGN-020 and NKCC1 antagonist bumetanide significantly reduced spinal cord edema, tissue destruction, and AQP4 and NKCC1 expression after SCI in an additive manner. These results demonstrated the benefits of simultaneously inhibiting both AQP4 and NKCC1 after SCI.

Involvement of serotonergic, noradrenergic and dopaminergic systems in the antidepressant-like effect of ginsenoside Rb1, a major active ingredient of Panax ginseng C.A. Meyer

ETHNOPHARMACOLOGY RELEVANCE

Ginsenoside Rb1, a 20 (S)-protopanaxadiol, is a major active ingredient of Panax ginseng C.A. Meyer, which as the King of Chinese herbs, has been wildly used for the treatment of central nervous system diseases. Previous studies have shown that 20 (S)-protopanaxadiol possesses a novel antidepressant-like effect in the treatment of depression, whereas ginsenoside Rb1 in depression has been rarely reported.

AIM OF THE REVIEW

The present study was to investigate the antidepressant-like effect of ginsenoside Rb1 and its relevant mechanisms.

MATERIALS AND METHODS

The whole experiment was divided into two parts: one part we examined the antidepressant-like effect of ginsenoside Rb1 with open-field test (OFT), tail suspension test (TST), forced swim test (FST), 5-HTP induced head-twitch and reserpine response in mice, another part we used chronic unpredicted mild stress (CUMS) model to further explore the antidepressant-like effect of ginsenoside Rb1 with caffeine, fluoxetine and p-Chlorophenylalanine (PCPA) in rats. Furthermore, the levels of monoamine neurotransmitters of NE, 5-HT, DA and their metabolites 5-HIAA, DOPAC, HVA were all measured by ELISA kits after the CUMS protocol.

RESULTS

Our data indicated that 7 days treatment with ginsenoside Rb1 (4, 8, 10mg/kg, p.o.) significantly decreased immobility time in the FST and TST in mice, and played important roles in mice which were induced by 5-HTP (200mg/kg, i.p.) and reserpine (4mg/kg, i.p.). On the basis of CUMS model, 21 days treatment with ginsenoside Rb1 not only had effective interactions with caffeine (5mg/kg, i.p.), fluoxetine (1mg/kg, i.p.) and PCPA (100mg/kg, i.p.), but also significantly up-regulated the 5-HT, 5-HIAA, NE and DA levels in CUMS rats' brain, whereas HVA and DOPAC had no significant difference. Moreover, there was no alteration in spontaneous locomotion in any experimental group.

CONCLUSIONS

These results suggest that ginsenoside Rb1 exhibits significant antidepressant-like effect in behavioral tests, chronic animal model and drug interactions, its mechanisms mainly mediated by central neurotransmitters of serotonergic, noradrenergic and dopaminergic systems.

Ginsenoside Rg3 Improves Recovery from Spinal Cord Injury in Rats via Suppression of Neuronal Apoptosis, Pro-Inflammatory Mediators, and Microglial Activation

Spinal cord injury (SCI) is one of the most devastating medical conditions; however, currently, there are no effective pharmacological interventions for SCI. Ginsenoside Rg3 (GRg3) is one of the protopanaxadiols that show anti-inflammatory, anti-oxidant, and neuroprotective effects. The present study investigated the neuroprotective effect of GRg3 following SCI in rats. SCI was induced using a static compression model at vertebral thoracic level 10 for 5 min. GRg3 was administrated orally at a dose of 10 or 30 mg/kg/day for 14 days after the SCI. GRg3 (30 mg/kg) treatment markedly improved behavioral motor functions, restored lesion size, preserved motor neurons in the spinal tissue, reduced Bax expression and number of TUNEL-positive cells, and suppressed mRNA expression of pro-inflammatory cytokines including tumor necrosis factor-α, interleukin (IL)-1β, and IL-6. GRg3 also attenuated the over-production of cyclooxygenase-2 and inducible nitric oxide synthase after SCI. Moreover, GRg3 markedly suppressed microglial activation in the spinal tissue. In conclusion, GRg3 treatment led to a remarkable recovery of motor function and a reduction in spinal tissue damage by suppressing neuronal apoptosis and inflammatory responses after SCI. These results suggest that GRg3 may be a potential therapeutic agent for the treatment of SCI.