title: Protective role of hydrogen sulfide against noise-induced cochlear damage: a chronic intracochlear infusion model.
abstract: BACKGROUND
  A reduction in cochlear blood flow plays an essential role in noise-induced hearing loss (NIHL). The timely regulation of cochlear perfusion determines the progression and prognosis of NIHL. Hydrogen sulfide (H(2)S) has attracted increasing interest as a vasodilator in cardiovascular systems. This study identified the role of H(2)S in cochlear blood flow regulation and noise protection.
  
  
  RESULTS
  The gene and protein expression of the H(2)S synthetase cystathionine-γ-lyase (CSE) in the rat cochlea was examined using immunofluorescence and real-time PCR. Cochlear CSE mRNA levels varied according to the duration of noise exposure. A chronic intracochlear infusion model was built and artificial perilymph (AP), NaHS or DL-propargylglycine (PPG) were locally administered. Local sodium hydrosulfide (NaHS) significantly increased cochlear perfusion post-noise exposure. Cochlear morphological damage and hearing loss were alleviated in the NaHS group as measured by conventional auditory brainstem response (ABR), cochlear scanning electron microscope (SEM) and outer hair cell (OHC) count. The highest percentage of OHC loss occurred in the PPG group.
  
  
  CONCLUSIONS
  Our results suggest that H(2)S plays an important role in the regulation of cochlear blood flow and the protection against noise. Further studies may identify a new preventive and therapeutic perspective on NIHL and other blood supply-related inner ear diseases.
authors: Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
authors: Xu
authors: X
authors: Li
authors: Xiao-Bo
authors: XB
authors: Mao
authors: Ren-Yi
authors: RY
authors: Hei
authors: Zhi-Bin
authors: ZB
authors: Zhang
authors: Li-Ting
authors: LT
authors: Wen
authors: Peng-Zhi
authors: PZ
authors: Zhang
authors: Jian-Hua
authors: JH
authors: Qiu
authors: Li
authors: L
authors: Qiao
mesh_terms: D000818:Animals; D003051:Cochlea / Q000098:blood supply / Q000293:injuries*; D016057:Evoked Potentials, Auditory, Brain Stem; D006317:Hearing Loss, Noise-Induced / Q000517:prevention & control*; D006862:Hydrogen Sulfide / Q000494:pharmacology*; D008954:Models, Biological; D009622:Noise / Q000009:adverse effects*; D020011:Protective Agents; D051381:Rats; D012039:Regional Blood Flow / Q000187:drug effects; D014665:Vasodilator Agents
chemical_list: D020011:Protective Agents; D014665:Vasodilator Agents; D006862:Hydrogen Sulfide