聋病基因研究新策略——基因敲除鼠听功能和内耳形态的系统研究

The general study on hearing function and inner ear morphology in knockout mice——A novel gene research strategy for deafness

虽然对听功能进行的研究已有进展,但目前对感音神经性聋的诊治仍是一大难题。聋病基因的发现使得我们可以从不同的层面揭示听觉功能的分子奥秘。但是,从功能基因组学角度看,仅仅发现和克隆聋病基因还远不是我们想达到的目标,需要进一步深入研究基因的功能。基因敲除是近年来发展和成熟起来的一项生物学新技术。通过在小鼠胚胎干细胞基因组水平的同源重组,造成目的基因的缺失突变,可以了解基因失活后对发育、生长、衰老以及器官、组织或细胞结构功能的影响,从而既可确切地从整体水平研究基因功能,又可建立疾病的动物模型。通过对内耳形态和听功能的系统研究,体现了功能基因组学的研究方向,并且可以建立基因缺陷致聋的动物模型。我们对SMAD4、SMAD5基因剔除小鼠进行了大量的听功能和内耳形态研究,发现基因缺陷导致小鼠严重听力障碍,并且内耳听觉器官包括毛细胞、支持细胞和螺旋神经节等出现不同程度的损害。可以认为,我们已经建立了一个基因缺陷导致聋病的动物模型。作为听功能基因研究新的平台,它将对听觉基因功能和聋病的分子机制研究有重要的意义,以此作为聋病基因研究的新策略,从而为最终的聋病基因治疗提供理论上的实验依据。

Deafness is one of most common disease in ear clinic, which may be caused by many reasons such as hereditary factor, viral infection, aging and physical factor and so on in the early stage of embryonic development. Up to now, it is still very difficult to have an effective therapy for the deafness patients especially with profound sensotineural heating loss. There were many reports in last decade showed the relative gene for deafness which have been cloned, but the more gratifying result should been focused on the function of the gene. Foremost among the recent advances in genetic manipulation of mouse genome are transgenic and embryonic stem （ES） cell technology. With these techniques, one can specifically address the function of a gene in vivo by introducing it into the mouse genome or by deleting the endogenous gene directly. Because the rest of the genome is well defined and inbred, physiologic of the inner ear differences between the genetically manipulated mice and their wild-type littermates can probably be attributed to the altered gene of interest, thus providing definitive evidence for its functional roles, such as hearing function. In present serious experiments, we showed the data from the smad4 and smad5 knockout mice. Our data indicate that smad4 and smad5 gene knockout in mice resulted in severe sensotineural heating loss, while there were transparent pathologic changes in inner ear of smad mutant mice, which indicates that smad mutant result in deficient in inner ear cells. In a word, a novel strategy, the general research on heating function combined with inner ear morphology in knockout mice, was recently developed to overcome the limitations of conventional heating research methods, which may be expected to be used as an animal model of the gene therapy for genetic heating loss.