Department of Otorhinolaryngology-Head and Neck Surgery, College of Medicine, Chung-Ang University, Seoul, South Korea.
Hear Res. 2011 Dec;282(1-2):236-42. doi: 10.1016/j.heares.2011.07.007. Epub 2011 Jul 23.
Lateral line system of the zebrafish is a useful model for study of hair cell toxicity and regeneration. We found that low molecular weight fucoidan (LMWF) stimulated the regeneration of mechanosensory hair cells after neomycin-induced cell death in zebrafish lateral line. The aims of this study were to quantify the regenerative effects of LMWF and determine their relationship to the Notch and FGF signaling pathways.
Wild-type zebrafish and three different transgenic zebrafish lines (Pou4f3::GFP, scm1::GFP, and ET20::GFP) were used. At 4.5-6 days post-fertilization, lateral line hair cells of larvae were eliminated using neomycin (500 μM). Larvae were then treated with LMWF. Neuromasts were observed using confocal microscopy. Stereocilia morphology was observed using scanning electron microscopy, and the location and status of regeneration was assessed using 5-bromo-2-deoxyuridine (BrdU) incorporation.
Hair cells damaged by neomycin treatment regenerated faster in wild-type and Pou4f3::GFP larvae treated with LMWF (50 μg/ml) than in untreated controls. LMWF also enhanced the regeneration of supporting cells in scm1::GFP and ET20::GFP larvae. Increased numbers of BrdU-labeled cells were found after LMWF treatment in neuromast regions corresponding to internal and peripheral supporting cells. The effect of LMWF was mimicked by the Notch signaling inhibitor N-[N-(3,5-difluorophenacetyl)-1-alanyl]-S-phenylglycine t-butyl ester (DAPT), but the effects of LMWF and DAPT were not additive.
LMWF enhances the regeneration of hair cells damaged by neomycin. The mechanism may involve the Notch signaling pathway. LMWF shows promise as a therapeutic agent for hearing and balance disorders.
斑马鱼的侧线系统是研究毛细胞毒性和再生的有用模型。我们发现，低分子量褐藻糖胶（LMWF）可刺激新霉素诱导的斑马鱼侧线毛细胞死亡后的机械感觉毛细胞再生。本研究的目的是量化 LMWF 的再生作用，并确定其与 Notch 和 FGF 信号通路的关系。
使用野生型斑马鱼和三种不同的转基因斑马鱼系（Pou4f3::GFP、scm1::GFP 和 ET20::GFP）。在受精后 4.5-6 天，使用新霉素（500 μM）消除幼虫的侧线毛细胞。然后用 LMWF 处理幼虫。使用共聚焦显微镜观察神经丘。使用扫描电子显微镜观察纤毛形态，并使用 5-溴-2-脱氧尿苷（BrdU）掺入评估再生的位置和状态。
与未处理的对照组相比，用 LMWF（50 μg/ml）处理的新霉素处理的野生型和 Pou4f3::GFP 幼虫的毛细胞再生更快。LMWF 还增强了 scm1::GFP 和 ET20::GFP 幼虫中支持细胞的再生。在 LMWF 处理后，在神经丘区域发现了更多的 BrdU 标记细胞，这些细胞对应于内部和外周支持细胞。Notch 信号通路抑制剂 N-[N-(3,5-二氟苯乙酰基）-1-丙氨酸]-S-苯甘氨酸叔丁酯（DAPT）模拟了 LMWF 的作用，但 LMWF 和 DAPT 的作用不是累加的。
LMWF 增强了新霉素损伤的毛细胞的再生。其机制可能涉及 Notch 信号通路。LMWF 有望成为治疗听力和平衡障碍的药物。
