Department of Otolaryngology-Head and Neck Surgery, First Hospital of Jilin University, Changchun, China.
PLoS One. 2013 Nov 21;8(11):e80854. doi: 10.1371/journal.pone.0080854. eCollection 2013.
The goals of this study were to investigate the effects of hypoxia on cochlear hair cell damage, and to explore the role of sirtuin1 in hypoxia-induced hair cell damage. Cochlear organotypic cultures from postnatal day 4 rats were used in this study. Hypoxia was induced by treating cochlear explants with CoCl2. Cochlear cultures were treated with CoCl2 alone or in combination with the sirtuin1 activator resveratrol and the sirtuin1 inhibitor sirtinol. Hair cell damage was identified by phalloidin staining and imaged using scanning electron microscopy. RT-PCR and Western blot analyses were used to detect the expression of sirtuin1 and acetylated nuclear factor-κB (NF-κB). Low concentrations of CoCl2 (100-200 μM) did not cause an obvious change in the number and morphology of hair cells, whereas higher concentrations of CoCl2 (300-400 μM) induced swelling of hair cells, accompanied by cell loss. Increased sirtuin1 expression was induced by CoCl2 at 100 to 200 μM, but not at 400 μM. NF-κB acetylation was significantly increased in explants treated with 400 μM CoCl2. Pretreatment with resveratrol prevented CoCl2-induced hair cell loss and acetylation of NF-κB. The protective effect of resveratrol was significantly reduced by sirtinol. CoCl2 induces hair cell damage in organotypic cochleae cultures. Resveratrol attenuates CoCl2-induced cochlear hair cell damage possibly via activation of sirtuin1, which deacetylates NF-κB.
本研究旨在探讨缺氧对耳蜗毛细胞损伤的影响，并探索沉默信息调节因子 1（Sirtuin1）在缺氧诱导的毛细胞损伤中的作用。该研究采用了来自出生后第 4 天大鼠的耳蜗器官型培养物。通过用 CoCl2 处理耳蜗外植体来诱导缺氧。耳蜗培养物单独用 CoCl2 处理或与 Sirtuin1 激活剂白藜芦醇和 Sirtuin1 抑制剂 Sirtinol 联合处理。通过鬼笔环肽染色和扫描电子显微镜成像来鉴定毛细胞损伤。通过 RT-PCR 和 Western blot 分析来检测 Sirtuin1 和乙酰化核因子-κB（NF-κB）的表达。低浓度的 CoCl2（100-200 μM）不会引起毛细胞数量和形态的明显变化，而较高浓度的 CoCl2（300-400 μM）会导致毛细胞肿胀，同时伴有细胞丢失。100-200 μM 的 CoCl2 诱导 Sirtuin1 表达增加，但 400 μM 的 CoCl2 则没有。NF-κB 乙酰化在 400 μM CoCl2 处理的外植体中显著增加。用白藜芦醇预处理可预防 CoCl2 诱导的毛细胞丢失和 NF-κB 的乙酰化。Sirtinol 显著降低了白藜芦醇的保护作用。CoCl2 可诱导器官型耳蜗培养物中的毛细胞损伤。白藜芦醇通过激活 Sirtuin1 减轻 CoCl2 诱导的耳蜗毛细胞损伤，Sirtuin1 可使 NF-κB 去乙酰化。
