title: Time evolution of noise induced oxidation in outer hair cells: role of NAD(P)H and plasma membrane fluidity.
abstract: BACKGROUND
  Noise exposure impairs outer hair cells (OHCs). The common basis for OHC dysfunction and loss by acoustic over-stimulation is represented by reactive oxygen species (ROS) overload that may affect the membrane structural organization through generation of lipid peroxidation.
  
  
  METHODS
  Here we investigated in OHC different functional zones the mechanisms linking metabolic functional state (NAD(P)H intracellular distribution) to the generation of lipid peroxides and to the physical state of membranes by two photon fluorescence microscopy.
  
  
  RESULTS
  In OHCs of control animals, a more oxidized NAD(P)H redox state is associated to a less fluid plasma membrane structure. Acoustic trauma induces a topologically differentiated NAD(P)H oxidation in OHC rows, which is damped between 1 and 6h. Peroxidation occurs after ~4h from noise insult, while ROS are produced in the first 0.2h and damage cells for a period of time after noise exposure has ended (~7.5h) when a decrease of fluidity of OHC plasma membrane occurs. OHCs belonging to inner rows, characterized by a lower metabolic activity with respect to other rows, show less severe metabolic impairment.
  
  
  CONCLUSIONS
  Our data indicate that plasma membrane fluidity is related to NAD(P)H redox state and lipid peroxidation in hair cells.
  
  
  CONCLUSIONS
  Our results could pave the way for therapeutic intervention targeting the onset of redox umbalance.
authors.affiliation: Istituto di Fisica, Università Cattolica (UCSC), Roma, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Maulucci
authors.affiliation: Istituto di Fisiologia, Università Cattolica (UCSC), Roma, Italy. Electronic address: d.troiani@rm.unicatt.it.
authors.forename: Diana
authors.initials: D
authors.lastname: Troiani
authors.affiliation: Istituto di Fisiologia, Università Cattolica (UCSC), Roma, Italy.
authors.forename: Sara Letizia Maria
authors.initials: SL
authors.lastname: Eramo
authors.affiliation: Dipartimento di Scienze Chirurgiche per le patologie della testa e del collo, Università Cattolica (UCSC), Roma, Italy.
authors.forename: Fabiola
authors.initials: F
authors.lastname: Paciello
authors.affiliation: Istituto di Fisiologia, Università Cattolica (UCSC), Roma, Italy.
authors.forename: Maria Vittoria
authors.initials: MV
authors.lastname: Podda
authors.affiliation: Dipartimento di Scienze Chirurgiche per le patologie della testa e del collo, Università Cattolica (UCSC), Roma, Italy.
authors.forename: Gaetano
authors.initials: G
authors.lastname: Paludetti
authors.affiliation: Istituto di Fisica, Università Cattolica (UCSC), Roma, Italy.
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Papi
authors.affiliation: Istituto di Fisica, Università Cattolica (UCSC), Roma, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Maiorana
authors.affiliation: Istituto di Fisica, Università Cattolica (UCSC), Roma, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Palmieri
authors.affiliation: Istituto di Fisica, Università Cattolica (UCSC), Roma, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: De Spirito
authors.affiliation: Dipartimento di Scienze Chirurgiche per le patologie della testa e del collo, Università Cattolica (UCSC), Roma, Italy.
authors.forename: Anna Rita
authors.initials: AR
authors.lastname: Fetoni
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000378:metabolism*; D004431:Ear, External / Q000378:metabolism / Q000473:pathology; D018072:Hair Cells, Auditory, Outer / Q000378:metabolism* / Q000473:pathology; D006317:Hearing Loss, Noise-Induced / Q000378:metabolism / Q000503:physiopathology; D015227:Lipid Peroxidation; D008560:Membrane Fluidity; D009249:NADP / Q000378:metabolism; D009622:Noise / Q000009:adverse effects*; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species; D009249:NADP
keywords: Acoustic trauma; Laurdan; Lipid peroxidation; Organ of Corti; Reactive oxygen species (ROS); Two-photon microscopy