title: Epigallocatechin gallate (EGCG) attenuates infrasound-induced neuronal impairment by inhibiting microglia-mediated inflammation.
abstract: Infrasound, a kind of common environmental noise and a major contributor of vibroacoustic disease, can induce the central nervous system (CNS) damage. However, no relevant anti-infrasound drugs have been reported yet. Our recent studies have shown that infrasound resulted in excessive microglial activation rapidly and sequential inflammation, revealing a potential role of microglia in infrasound-induced CNS damage. Epigallocatechin gallate (EGCG), a major bioactive component in green tea, has the capacity of protecting against various neurodegenerative diseases via an anti-inflammatory mechanism. However, it is still unknown to date whether EGCG acts on infrasound-induced microglial activation and neuronal damage. We showed that, after 1-, 2- or 5-day exposure of rats to 16 Hz, 130 dB infrasound (2 h/day), EGCG significantly inhibited infrasound-induced microglial activation in rat hippocampal region, evidenced by reduced expressions of Iba-1 (a marker for microglia) and proinflammatory cytokines (IL-1β, IL-6, IL-18 and TNF-α). Moreover, infrasound-induced neuronal apoptosis in rat hippocampi was significantly suppressed by EGCG. EGCG also inhibited infrasound-induced activation of primary microglia in vitro and decreased the levels of proinflammatory cytokines in the supernatants of microglial culture, which were toxic to cultured neurons. Furthermore, EGCG attenuated infrasound-induced increases in nuclear NF-κB p65 and phosphorylated IκBα, and ameliorated infrasound-induced decrease in IκB in microglia. Therefore, our study provides the first evidence that EGCG acts against infrasound-induced neuronal impairment by inhibiting microglia-mediated inflammation through a potential NF-κB pathway-related mechanism, suggesting that EGCG can be used as a promising drug for the treatment of infrasound-induced CNS damage.
authors.affiliation: Department of Neurology, Xijing hospital, Fourth Military Medical University, Xi'an 710032, China; Department of Endocrinology and Metabolism, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Cai
authors.affiliation: Department of Biomedical Engineering, Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Da
authors.initials: D
authors.lastname: Jing
authors.affiliation: Department of Neurology, Xijing hospital, Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Shi
authors.affiliation: Department of Neurology, Xijing hospital, Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Neurology, Xijing hospital, Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Tian
authors.initials: T
authors.lastname: Lin
authors.affiliation: Department of Neurology, Xijing hospital, Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Xie
authors.affiliation: Department of Neurology, Xijing hospital, Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Department of Neurology, Xijing hospital, Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Haibo
authors.initials: H
authors.lastname: Zhao
authors.affiliation: Department of Neurology, Xijing hospital, Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Xiaodan
authors.initials: X
authors.lastname: Shi
authors.affiliation: Department of Neurology, Xijing hospital, Fourth Military Medical University, Xi'an 710032, China. Electronic address: Dufang@fmmu.edu.cn.
authors.forename: Fang
authors.initials: F
authors.lastname: Du
authors.affiliation: Department of Neurology, Xijing hospital, Fourth Military Medical University, Xi'an 710032, China. Electronic address: zhaogang@fmmu.edu.cn.
authors.forename: Gang
authors.initials: G
authors.lastname: Zhao
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002392:Catechin / Q000031:analogs & derivatives* / Q000627:therapeutic use; D017077:Culture Media, Conditioned / Q000494:pharmacology; D016207:Cytokines / Q000378:metabolism; D007249:Inflammation / Q000517:prevention & control; D018836:Inflammation Mediators / Q000378:metabolism; D008297:Male; D017628:Microglia / Q000378:metabolism; D016328:NF-kappa B / Q000187:drug effects / Q000378:metabolism; D009474:Neurons / Q000187:drug effects*; D018696:Neuroprotective Agents / Q000627:therapeutic use*; D017207:Rats, Sprague-Dawley; D013016:Sound / Q000009:adverse effects*
chemical_list: D017077:Culture Media, Conditioned; D016207:Cytokines; D018836:Inflammation Mediators; D016328:NF-kappa B; D018696:Neuroprotective Agents; D002392:Catechin; C045651:epigallocatechin gallate
keywords: EGCG; Inflammation; Infrasound; Microglia; NF-κB; Neuronal damage