ABSTRACT
BACKGROUND AND OBJECTIVES: Platelet-activating factor (PAF) has been reported to be an active mediator of inflammation and ischemic damage in many organs. It plays a significant role in the pathogenesis of middle ear effusion. However, there have been few reports concerning the effects of PAF on inner ear and inner ear blood flow. This study determined the effects of PAF on the relation of cochlear blood flow (CBF) in guinea pigs. MATERIALS AND METHODS: The round window membrane (RWM) in each of 26 guinea pigs was exposed by dorsal approach and PAF was applied on it by Gelfoam pledgets. CBF of the basal turn was monitored using a laser Doppler flowmetry with the systemic blood pressure and changes in CBF being monitored, recorded and analysed. Epinephrine and normal saline were applied in the same manner as positive and negative controls, respectively. RESULTS: CBF was significantly reduced by the epinephrine application as a positive control. PAF applied at a concentration of 10 microgram/ml significantly increased CBF, while PAF applied at a concentration of 200 microgram/ml significantly reduced CBF. CONCLUSION: PAF did not induce ischemic damages when applied in the same concentration as the middle ear effusion fluid. However, when PAF was applied in excess, cochlear ischemia might be one of the mechanisms of inner ear damage it causes.