Amelioration of Mouse Retinal Degeneration After Blue LED Exposure by Glycyrrhizic Acid-Mediated Inhibition of Inflammation
Glycyrrhizic acid (GA) is a major component in the root and rhizomes of licorice (Glycyrrhiza glabra), which have been used as an herbal medicine, because of its anti-inflammatory activity. GA is known as an inhibitor of high-mobility group box 1 (HMGB1), which is involved in the pathogenesis of var...
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doaj-7760888a96e449c59dcaaa7f6f3552602020-11-24T22:12:40ZengFrontiers Media S.A.Frontiers in Cellular Neuroscience1662-51022019-07-011310.3389/fncel.2019.00319466697Amelioration of Mouse Retinal Degeneration After Blue LED Exposure by Glycyrrhizic Acid-Mediated Inhibition of InflammationGyu Hyun Kim0Sun-Sook Paik1Yong Soo Park2Hyoun Geun Kim3In-Beom Kim4In-Beom Kim5Department of Anatomy, College of Medicine, The Catholic University of Korea, Seoul, South KoreaDepartment of Anatomy, College of Medicine, The Catholic University of Korea, Seoul, South KoreaDepartment of Anatomy, College of Medicine, The Catholic University of Korea, Seoul, South KoreaDepartment of Anatomy, College of Medicine, The Catholic University of Korea, Seoul, South KoreaDepartment of Anatomy, College of Medicine, The Catholic University of Korea, Seoul, South KoreaCatholic Institute for Applied Anatomy, College of Medicine, The Catholic University of Korea, Seoul, South KoreaGlycyrrhizic acid (GA) is a major component in the root and rhizomes of licorice (Glycyrrhiza glabra), which have been used as an herbal medicine, because of its anti-inflammatory activity. GA is known as an inhibitor of high-mobility group box 1 (HMGB1), which is involved in the pathogenesis of various inflammatory diseases including inner retinal neuropathy. In this study, we examined the effect of GA in a mouse model of retinal degeneration (RD), the leading cause of blindness. RD was induced by exposure to a blue light-emitting diode (LED). In functional assessment, electroretinography showed that the amplitudes of both a- and b-waves were reduced in RD mice, whereas they were significantly increased in GA-treated RD mice (P < 0.05), compared to those in non-treated RD animals. In histological assessment, GA treatment preserved the outer nuclear layer where photoreceptors reside and reduced photoreceptor cell death. GA-treated retinas showed significantly reduced expression of proinflammatory cytokines such as TNF-α, IL-6, IL-1β, CCL2 and 6, iNOS, and COX-2 (P < 0.05), compared to that in non-treated retinas. Immunohistochemistry showed that Iba-1 and GFAP expression was markedly reduced in GA-treated retinas, indicating decreased glial response and inflammation. Interestingly, HMGB1 expression was reduced in non-treated RD retinas whereas GA paradoxically increased its expression. These results demonstrate that GA preserves retinal structure and function by inhibiting inflammation in blue LED-induced RD, suggesting a potential application of GA as a medication for RD. In addition, we propose a potential retinal protective function of HMGB1 in the pathogenesis of RD.https://www.frontiersin.org/article/10.3389/fncel.2019.00319/fullglycyrrhizic acidHMGB1inflammationphotoreceptorretinal degeneration |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Gyu Hyun Kim Sun-Sook Paik Yong Soo Park Hyoun Geun Kim In-Beom Kim In-Beom Kim |
spellingShingle |
Gyu Hyun Kim Sun-Sook Paik Yong Soo Park Hyoun Geun Kim In-Beom Kim In-Beom Kim Amelioration of Mouse Retinal Degeneration After Blue LED Exposure by Glycyrrhizic Acid-Mediated Inhibition of Inflammation Frontiers in Cellular Neuroscience glycyrrhizic acid HMGB1 inflammation photoreceptor retinal degeneration |
author_facet |
Gyu Hyun Kim Sun-Sook Paik Yong Soo Park Hyoun Geun Kim In-Beom Kim In-Beom Kim |
author_sort |
Gyu Hyun Kim |
title |
Amelioration of Mouse Retinal Degeneration After Blue LED Exposure by Glycyrrhizic Acid-Mediated Inhibition of Inflammation |
title_short |
Amelioration of Mouse Retinal Degeneration After Blue LED Exposure by Glycyrrhizic Acid-Mediated Inhibition of Inflammation |
title_full |
Amelioration of Mouse Retinal Degeneration After Blue LED Exposure by Glycyrrhizic Acid-Mediated Inhibition of Inflammation |
title_fullStr |
Amelioration of Mouse Retinal Degeneration After Blue LED Exposure by Glycyrrhizic Acid-Mediated Inhibition of Inflammation |
title_full_unstemmed |
Amelioration of Mouse Retinal Degeneration After Blue LED Exposure by Glycyrrhizic Acid-Mediated Inhibition of Inflammation |
title_sort |
amelioration of mouse retinal degeneration after blue led exposure by glycyrrhizic acid-mediated inhibition of inflammation |
publisher |
Frontiers Media S.A. |
series |
Frontiers in Cellular Neuroscience |
issn |
1662-5102 |
publishDate |
2019-07-01 |
description |
Glycyrrhizic acid (GA) is a major component in the root and rhizomes of licorice (Glycyrrhiza glabra), which have been used as an herbal medicine, because of its anti-inflammatory activity. GA is known as an inhibitor of high-mobility group box 1 (HMGB1), which is involved in the pathogenesis of various inflammatory diseases including inner retinal neuropathy. In this study, we examined the effect of GA in a mouse model of retinal degeneration (RD), the leading cause of blindness. RD was induced by exposure to a blue light-emitting diode (LED). In functional assessment, electroretinography showed that the amplitudes of both a- and b-waves were reduced in RD mice, whereas they were significantly increased in GA-treated RD mice (P < 0.05), compared to those in non-treated RD animals. In histological assessment, GA treatment preserved the outer nuclear layer where photoreceptors reside and reduced photoreceptor cell death. GA-treated retinas showed significantly reduced expression of proinflammatory cytokines such as TNF-α, IL-6, IL-1β, CCL2 and 6, iNOS, and COX-2 (P < 0.05), compared to that in non-treated retinas. Immunohistochemistry showed that Iba-1 and GFAP expression was markedly reduced in GA-treated retinas, indicating decreased glial response and inflammation. Interestingly, HMGB1 expression was reduced in non-treated RD retinas whereas GA paradoxically increased its expression. These results demonstrate that GA preserves retinal structure and function by inhibiting inflammation in blue LED-induced RD, suggesting a potential application of GA as a medication for RD. In addition, we propose a potential retinal protective function of HMGB1 in the pathogenesis of RD. |
topic |
glycyrrhizic acid HMGB1 inflammation photoreceptor retinal degeneration |
url |
https://www.frontiersin.org/article/10.3389/fncel.2019.00319/full |
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