title: Ethanolic extract from Hemidesmus indicus (Linn) displays otoprotectant activities on organotypic cultures without interfering on gentamicin uptake.
abstract: The ethanolic extract from Hemidesmus indicus (Linn) (Apocynaceae) (Hie) was studied for its otoprotective effects in ex vivo rat organotypic model of gentamicin (GM) toxicity. In organ of Corti organotypic cultures (OC), GM can induce a fast dose-dependent apoptosis of hair cells (HC), both external and internal. We found that, after coadministration of GM and Hie to organotypic cultures, the extract was able to significantly counteract this toxic effect on HC, at the concentration of 25 and 50microg/ml. Interestingly, at these concentrations the extract was present in the cell medium at a concentration 1.6- and 3.3-fold lower than GM, suggesting its otoprotective activity could not merely due to an aspecific inhibition of GM entry. To support this hypothesis, we evaluated the amount of GM present in organotypic cultures after the coadministration of 1.5mg/ml GM and Hie, and found no significant reduction of GM uptake in the presence of 100microg/ml Hie. These data suggest the otoprotective action of Hie derives from specific inhibition of the apoptotic routine induced by GM treatment.
authors.affiliation: Department of Morphology and Embryology, Human Anatomy Division, University of Ferrara, via Fossato di Mortara 66, 44100 Ferrara, Italy. prm@unife.it
authors.forename: Maurizio
authors.initials: M
authors.lastname: Previati
authors.forename: Elisa
authors.initials: E
authors.lastname: Corbacella
authors.forename: Laura
authors.initials: L
authors.lastname: Astolfi
authors.forename: Marco
authors.initials: M
authors.lastname: Catozzi
authors.forename: Mahmud Tareq Hassan
authors.initials: MT
authors.lastname: Khan
authors.forename: Ilaria
authors.initials: I
authors.lastname: Lampronti
authors.forename: Roberto
authors.initials: R
authors.lastname: Gambari
authors.forename: Silvano
authors.initials: S
authors.lastname: Capitani
authors.forename: Alessandro
authors.initials: A
authors.lastname: Martini
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000633:toxicity*; D003051:Cochlea / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D000431:Ethanol; D005839:Gentamicins / Q000633:toxicity*; D006198:Hair Cells, Auditory / Q000187:drug effects*; D031102:Hemidesmus / Q000737:chemistry*; D018696:Neuroprotective Agents / Q000494:pharmacology*; D009924:Organ Culture Techniques; D010936:Plant Extracts / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000900:Anti-Bacterial Agents; D005839:Gentamicins; D018696:Neuroprotective Agents; D010936:Plant Extracts; D000431:Ethanol