title: The Antioxidant N-Acetylcysteine Inhibits Inflammatory and Apoptotic Processes in Human Conjunctival Epithelial Cells in a High-Glucose Environment.
abstract: OBJECTIVE
  We evaluated the effects of N-acetylcysteine (NAC), which is known to inhibit reactive oxygen species (ROS)-dependent apoptosis, on high glucose-induced ROS, apoptosis, inflammation, and delayed-wounding closure in primary cultured human conjunctival epithelial cells (pHCECs), and the regulatory effects of cleaved caspase-3, BAX, nuclear factor κB (NF-κB), IL-6, and TNF-α on these processes.
  
  
  METHODS
  High glucose-induced ROS generation was measured using 2',7'-dichlorofluorescein diacetate (DCFH-DA). The effects of NAC on high glucose-induced apoptosis were investigated in pHCECs using Annexin-V and PI staining, and cleaved caspase-3 and BAX expression levels using immunoblotting. To evaluate the inflammatory response, IL-6 and TNF-α expression levels were quantified by multiplex cytokine analysis, and NF-κB activation and IkB-α degradation were assessed by Western blot analysis. The effects of NAC on high glucose-delayed conjunctival epithelial wound healing were assessed by a scratch-induced directional wounding assay.
  
  
  RESULTS
  Compared to the untreated control and normal glucose (5 mM), high glucose at 25 mM stimulated ROS generation, apoptosis, and release of inflammatory cytokines, and delayed wound healing in pHCECs. The addition of NAC markedly reduced the high glucose-induced ROS activation, Annexin-PI-positive cells, and levels of cleaved caspase-3, BAX, IL-6, and TNF-α. N-acetylcysteine also prevented high glucose-delayed wound healing.
  
  
  CONCLUSIONS
  High glucose levels promote apoptosis by affecting mitochondria-dependent caspase activity through elevation of ROS production, a process that can be reversed by the antioxidant NAC. These findings demonstrate that NAC has a beneficial effect on conjunctival epithelial cell wound healing, antiapoptosis, and anti-inflammation in the conjunctival epithelial cell.
authors: Department of Ophthalmology, University of Ulsan College of Medicine, Gangneng Asan Hospital, Gangneng, Republic of Korea.
authors: Jin Hyoung
authors: JH
authors: Park
authors: Research Institute for Biomacromolecules, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea.
authors: Soon-Suk
authors: SS
authors: Kang
authors: Research Institute for Biomacromolecules, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea 3Department of Ophthalmology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea.
authors: Jae Yong
authors: JY
authors: Kim
authors: Research Institute for Biomacromolecules, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea 3Department of Ophthalmology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea.
authors: Hungwon
authors: H
authors: Tchah
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology*; D000975:Antioxidants / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D002478:Cells, Cultured; D003228:Conjunctiva / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D005434:Flow Cytometry; D005947:Glucose / Q000494:pharmacology*; D006801:Humans; D006943:Hyperglycemia / Q000378:metabolism / Q000473:pathology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D000975:Antioxidants; D017382:Reactive Oxygen Species; D005947:Glucose; D000111:Acetylcysteine