The strategy to gain hearing ability of the deaf model mouse by injecting into the cochlea

遗传性耳聋的发病率约为1/2，000，而差距连接β 2蛋白（GJB 2）基因（即差距连接）的突变是各种族群体中的主要病因，因此需要在早期发育阶段进行正常的基因转移以预防耳聋。小鼠是内耳基因治疗的理想模型。为了建立治疗先天性耳聋的基础疗法，我们利用P0. 0控制的Cre重组酶对小鼠Gjb 2基因进行了靶向破坏。使用该动物模型，我们使用纯合突变小鼠和杂合突变小鼠检查了内耳基因治疗的潜力。将携带Gjb 2基因的腺相关病毒载体（AAV）经耳蜗圆窗注入纯合突变型成年小鼠的鼓阶。Cx 26在螺旋韧带和螺旋利姆布斯的纤维细胞中有表达，但在支持细胞中未见表达，对听力的改善作用不明显。然而，我们使用AAV成功地将基因导入没有听力损失的新生小鼠的支持细胞。本研究将提供关于在新生阶段将病毒载体引入Gjb 2基因敲除小鼠的初步数据。

Hereditary deafness affects about 1 in 2,000 children and mutations in the gap junction beta 2 protein (GJB2) gene, cording the gap junction, are the major cause in various ethnic groups, which require normal gene transfe r in the early developmental stage to prevent deafness. Mice present an ideal model for inner ear gene therapy. In order to establish the fundamental therapy of congenital deafness, we generated targeted disruption of mouse Gjb2 gene using Cre recombinase controlled by P0. Using this animal model, we examined the potential of gene therapy in the inner ear, using the homozygous mutant mice and the heterozygous mutant mice. Adeno -associated virus vectors (AAV) carrying Gjb2 gene were injected into the scala tympani through the round window of the cochlea of the homozygous mutant adult mice. The expression of Cx26 was observed in the fibrocytes of the spiral ligament and spiral limbus, but was not seen in the supporting cells and failed to improve the hearing ability. However, we succeed in gene introduction to the supporting cells of neonatal mice without hearing loss using AAV. The present study will present the preliminary data regarding introduction of the virus vector into the Gjb2 knockout mouse at the neonatal stage.