Inhibition Effects of Vitamin D3 on the Production of Nitric Oxide, Cytokine and Reactive Oxygen Species in Lipopolysacharide-stimulated Glial Cells: a Comparison with other Anti-Oxidants

• Main Authors: Lee Chwan Wang, 李傳旺
• Other Authors: 王家儀
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/01249543570766875416

碩士 === 國防醫學院 === 生理學研究所 === 90 === 1,25-dihydroxyvitamin D3 (or Vit.D3), an active metabolite of vitamin D, is well known for its systemic regulatory role in the maintenance of calcium homeostasis. The receptors for Vit.D3 (VDR) are found in the CNS. Recent evidence also indicates its neuroprotective and antioxidant potential in the central nervous system (CNS). Glial cells are centrally involved in inflammatory and immunological responses in pathological conditions including neurodegenerative disease, ischemia and trauma. Neuronal injury is an activation of glial cells (reactive astrocytes or microglia), resulting in the production of reactive oxygen species (ROS), nitric oxide (NO) and the release of proinflammatory cytokines such as tumor necrosis factor-* (TNF-*). Because ROS mediate the signal for NFκB activation in glial cells, we examined the role of vitamin D3 acted as an antioxidant and compared with ROS scavengers, including superoxide dismutase (SOD), dimethyl and thiourea (DMTU), redox regulators, including reduced glutathione (reduced GSH), N-acetylcysteine (NAC), aminooxyacetic acid (AOAA) and buthionine sulfoximine (BSO), and antioxidants such as vitamin C, in the production of ROS induced by LPS. In this thesis, glial activation by LPS was used as models to investigate the role of ROS and redox status in the expression of iNOS and cytokines induced by LPS using primary culture of mixed glial cells. The expression of iNOS was estimated by measuring NO production using the Griess method for nitrite, a stable metabolite of NO. Quantitation of cytokines (TNF-*) was measured by enzyme linked immunosorbent assays (ELISA). ROS production was measured by 2,7-chlorofluorescin diacetate (DCF-DA). LPS elevated nitrite levels in a concentration-dependent manner, Vit.D3, AOAA and Vit.C concentration-dependently inhibited the elevation of nitrite levels by LPS. LPS increased intracellular ROS production which reached the maximum at 18 hours. Vit.D3, SOD and AOAA suppressed the ROS production. LPS increased TNFα near maximal levels following treatment for 6 hours. Vit.D3, AOAA, NAC and BSO decreased LPS-induced TNFα release from mixed glia. These results demostrate that Vit. D3 suppresses the production of NO, TNFα and ROS in LPS-stimulated glial cells, and more effective than other drug used in this study, suggesting that Vit. D3 may suppress the activation of glial cells during inflammatory reactions elicited by CNS infections or injuries.