The Response Of The Afferent Synapse In Inner Hair Cell After Exposed To The Aminoglycoside Antibiotic

ObjectiveObserve the morphology and function change of inner hair cell afferentsynapse in C57BL/6J mice after intraperitoneal injection Gentamycin Sulfate,and then to make further study of the relation between these changes and thehearing loss.MethodsFive weeks C57BL/6J mice, male or female, each group compose of sixmice. One group as a control which given the same dose of saline per day, theother groups each mouse intraperitoneal injection Gentamycin Sulfate(100mg/kg) every day administration14days consecutively after withdrawalthe drugs and observed until the28th day. Choose4th,7th,10th,14th,28thtime point respectively to test the ABR thresholds (Click&tone burst) andDPOAEs of the mice. At each time point, the temporal bones were collected.Samples used to Immunohistochemical and Western blot to observe theexpression of RIBEYE/CtBP2and GluR2&3.ResultsAfter administration the Gentamycin, the experimental group mice hearingloss from the4th day, and it seems to be the threshold is the most seriously inthe7th, however the10th,14th,28th thresholds are lower than the7th groupbut they are not significant(p>0.05), the10th,14th,28th thresholds are higherthan the control group(p<0.05). After injected the Gentamycin, the4th,7th, 10th,14th,28th each point synapse protein have significantly changedincluding RIBEYE/CtBP2and GluR2&3, and this change reflect the thresholdof hearing.ConclusionThe hearing loss result by certain amount dosage of Gentamycin mayhave the relation to the afferent synapse’ morphology and function of inner haircell, once the recovery of the synapse’ morphology and function it maycontribute to the improvement of the hearing.