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Glycyrrhizin (GL) is a major constituent of licorice root and has been suggested to inhibit the release of high mobility group box-1 (HMGB1), a protein considered representative of damage-associated molecular patterns. We found that GL bound HMGB1 but not RAGE with a moderate equilibrium dissociation constant value based on surface plasmon resonance analysis. This complex formation prevented HMGB1 from binding to RAGE in vitro. The effects of glycyrrhizin on traumatic brain injury (TBI) induced by fluid percussion were examined in rats or mice in the present study. GL was administered intravenously after TBI. Treatment of rats with GL dose-dependently suppressed the increase in BBB permeability and impairment of motor functions, in association with the inhibition of HMGB1 translocation in neurons in injured sites. The beneficial effects of GL on motor and cognitive functions persisted for 7 days after injury. The expression of TNF-α, IL-1β and IL-6 in injured sites was completely inhibited by GL treatment. In RAGE-/- mice, the effects of GL were not observed. These results suggested that GL may be a novel therapeutic agent for TBI through its interference with HMGB1 and RAGE interaction., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Traumatic brain injury (TBI) is one of the major causes of death and aftereffects in young individuals worldwide; however, efficient therapies for TBI are lacking at present. High mobility group box-1 (HMGB-1), which is recognized as a representative of danger-associated molecular patterns (DAMPs), plays an important role in triggering inflammatory responses in many types of diseases. We presented the involvement of HMGB-1 in TBI and evaluated the ability of intravenously administered neutralizing anti-HMGB-1 monoclonal antibody (mAb) to attenuate brain injury. Anti-HMGB-1 mAb may provide a novel and effective therapy for TBI by protecting against blood brain barrier disruption and reducing the inflammatory responses induced by HMGB-1.

Traumatic brain injury (TBI) sustained in a traffic accident or a fall is a major cause of death that affects a broad range of ages. The aim of this study was to investigate the therapeutic effects of intra-arterial transplantation of mesenchymal stem cells (MSCs) combined with hypertonic glycerol (25%) or mannitol (25%) in a TBI model of rats. TBI models were produced with a fluid percussion device. At 24h after TBI, MSCs (1×10(6)cells/100μl) with glycerol or mannitol were administered via the right internal carotid artery. Rats were evaluated behaviorally and immunohistochemically, and hyperpermeability of the blood-brain barrier (BBB) induced by hypertonic solutions was explored. Compared to PBS or glycerol, the administration of mannitol resulted in increased BBB disruption. The mannitol-treated rats showed significant improvement in motor function. Intra-arterial transplantation of MSCs caused no thromboembolic ischemia. Immunohistochemically, more MSCs were observed in the injured brain tissues of mannitol-treated rats than in glycerol or PBS-treated rats at 24h after transplantation. Intra-arterial transplantation of MSCs combined with mannitol is an effective treatment in a TBI model of rats. This technique might be used for patients with diseases of the central nervous system including TBI., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

Objective: High mobility group box-1 (HMGB1) plays an important role in triggering inflammatory responses in many types of diseases. In this study, we examined the involvement of HMGB1 in traumatic brain injury (TBI) and evaluated the ability of intravenously administered neutralizing anti-HMGB1 monoclonal antibody (mAb) to attenuate brain injury., Methods: Traumatic brain injury was induced in rats or mice by fluid percussion. Anti-HMGB1 mAb or control mAb was administered intravenously after TBI., Results: Anti-HMGB1 mAb remarkably inhibited fluid percussion-induced brain edema in rats, as detected by T2-weighted magnetic resonance imaging; this was associated with inhibition of HMGB1 translocation, protection of blood-brain barrier (BBB) integrity, suppression of inflammatory molecule expression, and improvement of motor function. In contrast, intravenous injection of recombinant HMGB1 dose-dependently produced the opposite effects. Experiments using receptor for advanced glycation end product (RAGE)(-/-) , toll-like receptor-4 (TLR4)(-/-) , and TLR2(-/-) mice suggested the involvement of RAGE as the predominant receptor for HMGB1., Interpretation: Anti-HMGB1 mAb may provide a novel and effective therapy for TBI by protecting against BBB disruption and reducing the inflammatory responses induced by HMGB1., (Copyright © 2012 American Neurological Association.)

Background High mobility group box 1 (HMGB1) protein plays a key role in triggering inflammatory responses in many diseases. Our previous study showed that HMGB1 is found upstream of secondary damage in traumatic brain injury (TBI). We found that anti-HMGB1 monoclonal antibody (mAb) effectively decreased acute brain damage, including the disruption of the blood-brain barrier, brain edema, and neurologic dysfunction. This effect of anti-HMGB1 mAb lasts for at least 1 week. In this study, we explored subacute effects of anti-HMGB1 mAb after TBI. Methods TBI was induced in rats by fluid percussion. Anti-HMGB1 mAb or control mAb was given intravenously after TBI. Histochemical staining, plasma levels of HMGB1, motor activity and memory, and video electroencephalography monitoring were evaluated 2 weeks after fluid percussion injury. Results Anti-HMGB1 mAb remarkably attenuated accumulation of activated microglia in the rat cortex in the ipsilateral hemisphere after TBI. Anti-HMGB1 mAb also prevented neuronal death in the hippocampus in the ipsilateral hemisphere after TBI. Treatment of rats with anti-HMGB1 mAb inhibited HMGB1 translocation and suppressed impairment of motor function. The beneficial effects of anti-HMGB1 mAb on motor and cognitive function persisted for 14 days after injury. Treatment with anti-HMGB1 mAb also had positive effects on electroencephalography activity. Conclusions The beneficial effects of anti-HMGB1 mAb continued during the subacute postinjury phase, suggesting that anti-HMGB1 mAb may prevent cognitive dysfunction after TBI. [ABSTRACT FROM AUTHOR]