title: Brazilian green propolis suppresses the hypoxia-induced neuroinflammatory responses by inhibiting NF-κB activation in microglia.
abstract: Hypoxia has been recently proposed as a neuroinflammatogen, which drives microglia to produce proinflammatory cytokines, including interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and IL-6. Considering the fact that propolis has hepatoprotective, antitumor, antioxidative, and anti-inflammatory effects, propolis may have protective effects against the hypoxia-induced neuroinflammatory responses. In this study, propolis (50 μg/mL) was found to significantly inhibit the hypoxia-induced cytotoxicity and the release of proinflammatory cytokines, including IL-1β, TNF-α, and IL-6, by MG6 microglia following hypoxic exposure (1% O2, 24 h). Furthermore, propolis significantly inhibited the hypoxia-induced generation of reactive oxygen species (ROS) from mitochondria and the activation of nuclear factor-κB (NF-κB) in microglia. Moreover, systemic treatment with propolis (8.33 mg/kg, 2 times/day, i.p.) for 7 days significantly suppressed the microglial expression of IL-1β, TNF-α, IL-6, and 8-oxo-deoxyguanosine, a biomarker for oxidative damaged DNA, in the somatosensory cortex of mice subjected to hypoxia exposure (10% O2, 4 h). These observations indicate that propolis suppresses the hypoxia-induced neuroinflammatory responses through inhibition of the NF-κB activation in microglia. Furthermore, increased generation of ROS from the mitochondria is responsible for the NF-κB activation. Therefore, propolis may be beneficial in preventing hypoxia-induced neuroinflammation.
authors: Department of Aging Science and Pharmacology, Faculty of Dental Science, Kyushu University, Fukuoka 812-8582, Japan. zhouw@dent.kyushu-u.ac.jp
authors: Zhou
authors: Z
authors: Wu
authors: Aiqin
authors: A
authors: Zhu
authors: Fumiko
authors: F
authors: Takayama
authors: Ryo
authors: R
authors: Okada
authors: Yicong
authors: Y
authors: Liu
authors: Yuka
authors: Y
authors: Harada
authors: Shizheng
authors: S
authors: Wu
authors: Hiroshi
authors: H
authors: Nakanishi
mesh_terms: D000818:Animals; D015687:Cell Hypoxia / Q000187:drug effects / Q000502:physiology*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004586:Electrophoresis; D004797:Enzyme-Linked Immunosorbent Assay; D015151:Immunoblotting; D051379:Mice; D017628:Microglia / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism; D011429:Propolis / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D016328:NF-kappa B; D017382:Reactive Oxygen Species; D011429:Propolis
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