Lee Sang-Yeon, Han Sang Yoon, Shim Ye-Ji, Han Jae-Joon, Cho DeukTae, Kim Ji Eun, Kim Young Ho
Department of Otorhinolaryngology-Head and Neck Surgery, SMG-SNU Boramae Medical Center, Seoul National University College of Medicine, Seoul, Korea.
Department of Pathology, SMG-SNU Boramae Medical Center, Seoul National University College of Medicine, Seoul, Korea.
Clin Exp Otorhinolaryngol. 2019 May;12(2):169-175. doi: 10.21053/ceo.2018.00983. Epub 2018 Oct 27.
Sodium salicylate (SS) is well known for its ototoxic properties that induce functional and morphological changes in the cochlea and brain. Ginkgo biloba extract (GBE) has been widely used for treatment of various neurodegenerative diseases; however, its effects on salicylate-induced ototoxicity remain unclear. Herein, we examined the effects of EGb 761 (EGb), a standard form of GBE, on the plasticity of the N-methyl-D-aspartate receptor subunit 2B (GluN2B) in the inferior colliculus (IC) following SS administration.
Seven-week-old Sprague Dawley rats (n=24) were randomly allocated to control, SS, EGb, and EGb+SS groups. The SS group received a single intraperitoneal SS injection (350 mg/kg), the EGb group received EGb orally for 5 consecutive days (40 mg/kg), and the EGb+SS group received EGb for 5 consecutive days, followed by an SS injection. The auditory brainstem responses (ABRs) were assessed at baseline and 2 hours after SS administration. GluN2B expression was examined by Western blot and immunohistochemistry.
There were no significant differences in ABR threshold shifts among the groups. The expression of the GluN2B protein normalized by which of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) was significantly lower in the EGb+SS group, as compared to the SS group (P=0.012). Weak and diffused GluN2B immunoreactivity was detected in the IC neural cells of the EGb+SS group, while those of the SS group exhibited strong and diffused GluN2B positivity.
EGb may play a role in regulating the GluN2B expression in the IC of salicylate-induced ototoxicity model.
水杨酸钠（SS）因其耳毒性特性而闻名，可导致耳蜗和大脑发生功能及形态变化。银杏叶提取物（GBE）已被广泛用于治疗各种神经退行性疾病；然而，其对水杨酸盐诱导的耳毒性的影响仍不清楚。在此，我们研究了GBE的标准形式EGb 761（EGb）对SS给药后下丘（IC）中N-甲基-D-天冬氨酸受体亚基2B（GluN2B）可塑性的影响。
将7周龄的Sprague Dawley大鼠（n = 24）随机分为对照组、SS组、EGb组和EGb + SS组。SS组接受单次腹腔注射SS（350 mg/kg），EGb组连续5天口服EGb（40 mg/kg），EGb + SS组连续5天接受EGb治疗，随后注射SS。在基线和SS给药后2小时评估听觉脑干反应（ABR）。通过蛋白质印迹法和免疫组织化学法检测GluN2B表达。
各组之间ABR阈值变化无显著差异。与SS组相比，EGb + SS组中以甘油醛-3-磷酸脱氢酶（GAPDH）标准化的GluN2B蛋白表达显著降低（P = 0.012）。在EGb + SS组的IC神经细胞中检测到弱且弥散的GluN2B免疫反应性，而SS组的神经细胞则表现出强且弥散的GluN2B阳性。
EGb可能在调节水杨酸盐诱导的耳毒性模型的IC中GluN2B表达方面发挥作用。
