The possible protective role of aminoguanidine ingentamicin-induced ototoxicity in guinea pig: a histologicaland immunohistochemical study

IntroductionGentamicin is an ototoxic drug affecting both auditory and vestibular cells. Reactiveoxygen species might play important role in the molecular pathway of this ototoxicity.Aminoguanidine is one of the guanidine derivatives and is considered as anantioxidant therapy.Aim of the workto investigate the possible protective effect of aminoguanidine on ototoxicity inducedby gentamicin in guinea pig.Materials and methodsTwenty one adult male guinea pigs were used. They were divided into three groups,seven animals each. Group I: served as a control group. Group II: I.M. injectionof gentamicin (80 mg/kg/day) was used for 14 days. Group III: animals receivedgentamicin in the same way as group II and then followed by aminoguanidine (100mg/kg/ day) administration using a gastric tube for 14 days. At the end of experiment,the cochlea was excised and prepared for light (LM) and scanning electronmicroscope (SME) examination. Immunohistochemichal technique was done todetect iNOS. Morphometric and statistical studies were also done.ResultsBy LM and SME examination, the present study showed that aminoguanidineprotected the structure of organ of Corti in the cochlea by decreasing thedegeneration of hair cells and other supporting cells. It also showed a significantdecrease in the iNOS immune-reactivity in organ of Corti, stria vascularis and bipolarcells in spiral ganglia compared to group II.ConclusionAminoguanidine is a promising and successful antioxidant therapy for ototoxicity.