title: Short interfering RNA against Bax attenuates TNFα-induced ototoxicity in rat organ of Corti explants.
abstract: OBJECTIVE
  Evaluate the effectiveness of short interfering RNA against Bax (Bax siRNA) as a treatment for tumor necrosis factor α (TNFα)-induced auditory hair cell (HC) loss in rat organ of Corti (OC) explants.
  
  
  METHODS
  Basic science.
  
  
  METHODS
  Basic science laboratory, University of Miami Ear Institute.
  
  
  METHODS
  Organ of Corti explants dissected from 3-day-old rats were cultured in control media, TNFα, and TNFα + Bax siRNA at 0, 48, and 72 hours in vitro. Real-time polymerase chain reaction, enzyme-linked immunosorbent assay, HC viability studies, immunofluorescence, and confocal microscopy were performed. Analysis of variance with post hoc testing was used with P < .05 considered significant.
  
  
  RESULTS
  The TNFα-damaged explants demonstrated significant decreases in viable HCs in the basal turn with corresponding increased levels of Bax gene and protein expression, compared with control explant levels. The levels of viable HCs and Bax gene and protein expression in TNFα + Bax siRNA-treated explants approached levels measured in control explants. Immunolocalization studies showed increased Bax protein expression in basal turn HCs in TNFα-treated explants, whereas control explants and TNFα + Bax siRNA-treated explants had low levels of Bax expression.
  
  
  CONCLUSIONS
  TNFα initiates the programmed cell death of auditory HCs in OC explants through upregulation of proapoptotic Bax gene and protein expression. Bax siRNA blocks TNFα-induced apoptosis of HCs by decreasing the TNFα-induced levels of Bax mRNA and protein expression in treated explants. Bax siRNA is an effective treatment for TNFα-induced ototoxicity in OC explants in vitro and has great potential to be a therapeutic agent against trauma/inflammation-induced hearing loss.
authors: University of Miami Ear Institute, Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, Florida 33136, USA.
authors: Christine
authors: C
authors: Dinh
authors: Esperanza
authors: E
authors: Bas
authors: John
authors: J
authors: Dinh
authors: Ly
authors: L
authors: Vu
authors: Chhavi
authors: C
authors: Gupta
authors: Thomas R
authors: TR
authors: Van De Water
mesh_terms: D000818:Animals; D017209:Apoptosis; D002470:Cell Survival; D004195:Disease Models, Animal; D015870:Gene Expression; D006198:Hair Cells, Auditory / Q000187:drug effects; D034381:Hearing Loss / Q000209:etiology / Q000628:therapy*; D009925:Organ of Corti / Q000187:drug effects*; D034741:RNA, Small Interfering / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014409:Tumor Necrosis Factor-alpha / Q000009:adverse effects / Q000378:metabolism* / Q000494:pharmacology; D051028:bcl-2-Associated X Protein / Q000096:biosynthesis*
chemical_list: D034741:RNA, Small Interfering; D014409:Tumor Necrosis Factor-alpha; D051028:bcl-2-Associated X Protein