Farhadi Mohammad, Jalessi Maryam, Salehian Pirooz, Ghavi Farhid Farahmand, Emamjomeh Hesamedin, Mirzadeh Hamid, Imani Mohammad, Jolly Claude
ENT-Head and Neck Research Center and Department, Hazrat Rasool Akram Hospital, Tehran University of Medical Sciences, Tehran, Iran.
Cochlear Implants Int. 2013 Jan;14(1):45-50. doi: 10.1179/1754762811Y.0000000024.
New cochlear implant (CI) designs and developments in implantation techniques have revolutionized the management of hearing loss. However, cochlear implantation still has some disadvantages, such as its potential to initiate an inflammatory response that may lead to further hair cell damage. Recent topics of investigation have been the effect of glucocorticoids on inflammatory tissue response reduction, glucocorticoid dosage levels, and drug-delivery methods. In the present study, dexamethasone delivery via a drug-eluting CI was evaluated histologically through assessing inflammatory cell infiltration.
Thirty healthy, adult male guinea pigs were included and randomly assigned to one of three surgical groups that underwent cochleostomy of the basal turn. The experimental group (Group 1) of 12 animals were implanted with a dexamethasone-loaded silicone elastomer shaped like a CI electrode. The primary control group (Group 2) of 12 animals were implanted with a simple CI (non-eluting). A second control group (Group 3) of six animals underwent cochleostomy only. Inflammatory responses were compared between groups by evaluating inflammatory cell infiltration in inner-ear specimens at days 3 and 13.
The Mann‐Whitney test revealed reduction in most of the inflammatory indices in Group 1 compared with Group 2. This was significant for fibrocyte, macrophage, and giant cell infiltration at day 3 as well as lymphocyte, macrophage infiltration, and capillary formation at day 13.
This study showed some attenuation in inflammatory response following insertion of a dexamethasone-eluting CI, suggesting that it could be a route for local drug delivery into the cochlea.
新型人工耳蜗（CI）设计及植入技术的发展彻底改变了听力损失的治疗方式。然而，人工耳蜗植入仍存在一些缺点，比如其可能引发炎症反应，进而导致毛细胞进一步受损。近期的研究课题包括糖皮质激素对减轻炎症组织反应的作用、糖皮质激素剂量水平及给药方法。在本研究中，通过评估炎症细胞浸润，从组织学角度对经药物洗脱人工耳蜗递送地塞米松进行了评价。
纳入30只健康成年雄性豚鼠，并随机分为三个手术组之一，均接受蜗底转鼓阶造瘘术。实验组（第1组）的12只动物植入了形状类似CI电极的载地塞米松硅橡胶弹性体。第2组为主要对照组，12只动物植入简单人工耳蜗（无药物洗脱功能）。第3组为第二对照组，6只动物仅接受蜗底转鼓阶造瘘术。通过评估第3天和第13天内耳标本中的炎症细胞浸润情况，比较各组间的炎症反应。
Mann-Whitney检验显示，与第2组相比，第1组的大多数炎症指标有所降低。在第3天，成纤维细胞、巨噬细胞和巨细胞浸润以及在第13天淋巴细胞、巨噬细胞浸润和毛细血管形成方面，差异具有统计学意义。
本研究表明，插入地塞米松洗脱型人工耳蜗后炎症反应有所减轻，提示这可能是一种向耳蜗局部给药的途径。
