title: Basic fibroblast growth factor inhibits cell proliferation in cultured avian inner ear sensory epithelia.
abstract: Postembryonic production of inner ear hair cells occurs after insult in nonmammalian vertebrates. Recent studies suggest that the fibroblast family of growth factors may play a role in stimulating cell proliferation in mature inner ear sensory epithelium. Effects of acidic fibroblast growth factor (FGF-1) and basic fibroblast growth factor (FGF-2) were tested on progenitor cell division in cultured auditory and vestibular sensory epithelia taken from posthatch chickens. The effects of heparin, a glycosaminoglycan that often potentiates the effects of the FGFs, were also assessed. Tritiated-thymidine autoradiographic techniques and 5-bromo-2;-deoxyuridine (BrdU) immunocytochemistry were used to identify cells synthesizing DNA. The terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP)-biotin nick-end-label (TUNEL) method was used to identify apoptotic cells. TUNEL and overall counts of sensory epithelial cell density were used to assess possible cytotoxic effects of the growth factors. FGF-2 inhibited DNA synthesis in vestibular and auditory sensory epithelia and was not cytotoxic at the concentrations employed. FGF-1 did not significantly alter sensory epithelial cell proliferation. Heparin by itself inhibited DNA synthesis in the vestibular sensory epithelia and failed to potentiate the effects of FGF-1 or FGF-2. Heparin was not cytotoxic at the concentrations employed. Results presented here suggest that FGF-2 may be involved in inhibiting cell proliferation or stimulating precursor cell differentiation in avian inner ear sensory epithelia.
authors.affiliation: Virginia Merrill Bloedel Hearing Research Center and Department of Otolaryngology-HNS, University of Washington, Seattle, Washington 98195-7923, USA. oesterle@u.washington.edu
authors.forename: E C
authors.initials: EC
authors.lastname: Oesterle
authors.forename: S A
authors.initials: SA
authors.lastname: Bhave
authors.forename: M D
authors.initials: MD
authors.lastname: Coltrera
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D001798:Blood Proteins / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects* / Q000502:physiology; D002645:Chickens / Q000033:anatomy & histology / Q000378:metabolism*; D007758:Ear, Inner / Q000166:cytology / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D004848:Epithelium / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D016220:Fibroblast Growth Factor 1 / Q000378:metabolism / Q000494:pharmacology; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism / Q000494:pharmacology*; D006198:Hair Cells, Auditory / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D006493:Heparin / Q000494:pharmacology; D008938:Mitosis / Q000187:drug effects / Q000502:physiology; D012444:Saccule and Utricle / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D013234:Stem Cells / Q000187:drug effects* / Q000502:physiology
chemical_list: D001798:Blood Proteins; D016222:Fibroblast Growth Factor 2; D016220:Fibroblast Growth Factor 1; D006493:Heparin