title: The Antioxidant Effects of Thymoquinone in Activated BV-2 Murine Microglial Cells.
abstract: Both neuroinflammation and microglial activation are pathological markers of a number of central nervous system (CNS) diseases. During chronic activation of the microglial cells, the induced release of excessive amounts of reactive oxygen species (ROS) and pro-inflammatory cytokines have been implicated in several neurodegenerative diseases such as Alzheimer's disease. Thymoquinone (TQ), a major bioactive compound of the natural product Nigella sativa seed, has been shown to be effective against numerous oxidative stress-induced and inflammatory disorders as well as possess neuroprotective properties. In this study, we investigated the antioxidant effects of TQ on LPS/IFNγ or H2O2-activated BV-2 microglia by assessing the levels of specific oxidative stress markers, the activities of selected antioxidant enzymes, as well as profiling 84 key genes related to oxidative stress via real-time reverse transcription (RT2) PCR array. Our results showed that in the LPS/IFNγ-activated microglia TQ significantly decreased the cellular production of both superoxide and nitric oxide fourfold (p < 0.0001) and sixfold (p < 0.0001), respectfully. In the H2O2-activated microglia, TQ also significantly decreased the cellular production of superoxide threefold (p < 0.0001) and significantly decreased hydrogen peroxide levels ~20 % (p < 0.05). Moreover, ΤQ treatment significantly decreased the levels oxidative stress in the activated BV-2 as evidenced by the assessed levels of lipid hydroperoxides and glutathione. TQ significantly decreased the levels of lipid hydroperoxides twofold (p < 0.0001) and significantly increased the levels of antioxidant glutathione 2.5-fold (p < 0.0001) in the LPS/IFNγ-activated BV-2 cells. In the H2O2-activated microglia, TQ significantly decreased lipid hydroperoxides eightfold (p < 0.0001) and significantly increased glutathione 15 % (p < 0.05). Activities of antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT), in the TQ-treated microglial cells also reflected a reduced oxidative stress status in the cellular environment. SOD and CAT activities were sixfold (p < 0.0001) and fivefold (p < 0.0001) lower, respectfully, for the LPS/INFγ-activated microglia treated with TQ in comparison to those that were not. For the H2O2-activated microglia treated with TQ, SOD and CAT activities were fivefold (p < 0.0001) and threefold (p < 0.01) lower, respectfully, compared to the untreated. Furthermore, RT2PCR array profiling of the selected 84 genes related to oxidative stress confirmed that TQ treatment in the LPS/IFNγ-activated microglia downregulates specific pro-oxidant genes, upregulates specific anti-oxidant genes, and enhances the up- or downregulation of specific genes related to the cells' natural antioxidant defense against LPS/IFNγ activation. These findings suggest that TQ may be utilized as an effective therapeutic agent for delaying the onset and/or slowing/preventing the progression of microglia-derived neurodegeneration propagated by excessive oxidative stress in the CNS.
authors: College of Pharmacy and Pharmaceutical Sciences, Florida A&M University, Room 104 Dyson Pharmacy Building, 1520 ML King Blvd, Tallahassee, FL, 32307, USA.
authors: Makini K
authors: MK
authors: Cobourne-Duval
authors: College of Pharmacy and Pharmaceutical Sciences, Florida A&M University, Room 104 Dyson Pharmacy Building, 1520 ML King Blvd, Tallahassee, FL, 32307, USA.
authors: Equar
authors: E
authors: Taka
authors: College of Pharmacy and Pharmaceutical Sciences, Florida A&M University, Room 104 Dyson Pharmacy Building, 1520 ML King Blvd, Tallahassee, FL, 32307, USA.
authors: Patricia
authors: P
authors: Mendonca
authors: College of Pharmacy and Pharmaceutical Sciences, Florida A&M University, Room 104 Dyson Pharmacy Building, 1520 ML King Blvd, Tallahassee, FL, 32307, USA.
authors: David
authors: D
authors: Bauer
authors: College of Pharmacy and Pharmaceutical Sciences, Florida A&M University, Room 104 Dyson Pharmacy Building, 1520 ML King Blvd, Tallahassee, FL, 32307, USA. karam.soliman@famu.edu.
authors: Karam F A
authors: KF
authors: Soliman
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D016227:Benzoquinones / Q000494:pharmacology*; D002374:Catalase / Q000378:metabolism; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D005978:Glutathione / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism / Q000494:pharmacology; D007371:Interferon-gamma / Q000494:pharmacology; D008054:Lipid Peroxides / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D051379:Mice; D017628:Microglia / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis; D013482:Superoxide Dismutase / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism
chemical_list: D000975:Antioxidants; D016227:Benzoquinones; D008054:Lipid Peroxides; D008070:Lipopolysaccharides; D013481:Superoxides; D009569:Nitric Oxide; D007371:Interferon-gamma; D006861:Hydrogen Peroxide; D002374:Catalase; D013482:Superoxide Dismutase; D005978:Glutathione; C003466:thymoquinone
keywords: Microglia; Neurodegenerative disease; Oxidative stress; Thymoquinone