Oesterle E C, Bhave S A, Coltrera M D
Virginia Merrill Bloedel Hearing Research Center and Department of Otolaryngology-HNS, University of Washington, Seattle, Washington 98195-7923, USA.
J Comp Neurol. 2000 Aug 21;424(2):307-26. doi: 10.1002/1096-9861(20000821)424:2<307::aid-cne9>3.0.co;2-m.
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.
内耳毛细胞的胚后生成发生在非哺乳动物脊椎动物受到损伤之后。最近的研究表明，成纤维细胞生长因子家族可能在刺激成熟内耳感觉上皮细胞增殖中发挥作用。对孵化后小鸡的听觉和前庭感觉上皮细胞培养物中的祖细胞分裂，测试了酸性成纤维细胞生长因子（FGF-1）和碱性成纤维细胞生长因子（FGF-2）的作用。还评估了肝素（一种经常增强FGFs作用的糖胺聚糖）的作用。利用氚标记胸腺嘧啶核苷放射自显影技术和5-溴-2'-脱氧尿苷（BrdU）免疫细胞化学来鉴定合成DNA的细胞。采用末端脱氧核苷酸转移酶（TdT）介导的脱氧尿苷三磷酸（dUTP）-生物素缺口末端标记（TUNEL）法来鉴定凋亡细胞。TUNEL和感觉上皮细胞密度的总体计数用于评估生长因子可能的细胞毒性作用。FGF-2抑制前庭和听觉感觉上皮细胞中的DNA合成，在所采用的浓度下无细胞毒性。FGF-1未显著改变感觉上皮细胞增殖。肝素本身抑制前庭感觉上皮细胞中的DNA合成，且未能增强FGF-1或FGF-2的作用。在所采用的浓度下肝素无细胞毒性。此处给出的结果表明，FGF-2可能参与抑制鸟类内耳感觉上皮细胞的增殖或刺激前体细胞分化。
