γ分泌酶抑制剂DAPT对庆大霉素致大鼠耳损伤及修复过程中听力及Notch2/hes1信号通路表达的影响

摘要

目的 观察γ分泌酶抑制剂DAPT对庆大霉素致大鼠耳损伤及修复过程中听力变化及Notch2/hes1信号通路表达的影响.方法 72只成熟大鼠随机分成三组,每组24只;对照组给予生理盐水3 ml·kg-1·d-1 腹腔注射,连继10天,庆大霉素组给予Gen 120 mg·kg-1·d-1腹腔注射,连继10天,DAPT组给予DAPT 5 mg·kg-1·d-1腹腔注射,连用5天后停用2天,再用3天,同时腹腔注射Gen 120 mg·kg-1·d-1,连继10天.各组注射前及注射后1、14、28天进行ABR检测后处死动物,应用免疫印迹蛋白、实时定量PCR观察大鼠Notch2/hes1信号通路的表达.结果 对照组注射前后ABR反应阈无明显变化,与注射前相比,DAPT组和庆大霉素组注射后1、14、28天ABR阈值均明显升高,但随时间的延长阈值有所下降(P<0.05),其中,第28天DAPT组ABR反应阈较庆大霉素组下降明显(P<0.05);与对照组相比,DAPT组和庆大霉素组Notch2/hes1的表达均明显增高(P<0.05);与庆大霉素组相比,DAPT组的Notch2/hes1表达明显降低(P<0.05).结论 在庆大霉素致耳损伤及修复过程中,DAPT可能通过抑制Notch2/hes1信号通路减轻耳蜗毛细胞损伤并促进耳蜗毛细胞修复,进而促进听功能恢复.%Objective To study the effects of DAPT on hearing and Notch2/hesl signaling pathways expres sion in gentamicin-induced hearing injury and repair process. Methods Seventy-two mature rats were randomly divided into the normal group(saline, intraperitoneal injection, 3 ml · kg-1 · d-1 ,held following the ten days) ,mod el group(Gen,120 mg · kg-1 · d-1 , intraperitoneal injection, continuous ten days) and DAPT group(Gen,120 mg · kg-1 · d-1 , intraperitoneal injection, continuous ten days;DAPT,5 mg · kg-1 · d-1 intraperitoneal injection, held following the five days, continuous three days after stop two days). Hearing changes were evaluated by auditory brainstem response (ABR) at pre-modeling and 1,14 ,28 days post-modeling. The expression of the Notch2/hesl was detected by western -blotting and real-time quantitative PCR, at 1,14,28 days post-modeling. Results Au ditory brainstem response CABR) showed that the normal group had no significant change. Compared with those of before treatment, the ABR threshold were significantly higher and decreased with time in model group and in the DAPT group (P<0. 05). Real-time quantitative PCR and western-blotting showed that compared with the nor mal group, the expression level of Notch2hesl was significantly higher at 1,14,28 days in the model group and in DAPT group (P<0. 05). The expression level of Notch2hesl had evident decreae in the DAPT group compared with that of in the model group(P-<0. 05). Conclusion DAPT may reduce the hair cell damage and promote the repair of the hair cells by inhibiting Notch2/hes1 signaling pathways, thus contributing to the recovery of the hearing.