透明鲫—一个适合活体研究的鱼类模型

Transparent crucian carp Carassius auratus,a fish model suitable for study in vivo

目的了解鲫成体透明的原因,探讨该性状的应用特性,为透明鲫作为水生实验动物材料系统开发提供基础。方法对透明鲫进行繁殖,并观察其后代性状,了解透明性状的遗传规律;体视镜观察透明鲫色素细胞的种类与分布,并与鲫比较;组织切片和压片确认微孢子虫对透明鲫的感染,并观察感染症状的变化。结果鲫的透明性状可以遗传,大部分后代表现为通体透明,心、肝、肾、肠、鳔、鳃、脊椎等组织器官肉眼清晰可见。与正常鲫比较,透明鲫的主要色素细胞为黄色素细胞,并未发现虹彩色素细胞,黑色素细胞的数量也大为减少。微孢子虫对鱼体的感染过程可直观观察,病原的扩散和空间分布能实时获得,具普通鱼类无法比拟的应用优势。结论虹彩色素细胞的缺失是鲫透明突变的结构基础。由于透明鲫内部器官可直接观测,无需依靠解剖或复杂仪器系统,在同一动物身上可能获得一系列的动态试验数据,或可作为模型材料广泛应用于生命科学不同领域。

Objective To better understand the mechanism of transparency in adult crucian carp,explore its application and provide more evidence to support it as a novel aquatic animal model.Methods The transparent crucian carp was bred,and the phenotype of offsprings was examined to learn the inheritance of the transparent character.A stereomicroscope was used to examine the types and patterns of chromatophores in transparent and common crucian carps.The fish infected with microsporidia were closely monitored.Tissue sections and wet-mounted squashes were prepared to observe the parasites in muscle tissues,and tissue sections were used to characterize the pathological changes under the light microscope.Results The transparent fish were healthy and fertile,showing a inherent character.The mutants manifested as entire transparent body.The main internal organs,such as heart,liver,gut,kidney,swim bladder,gills,and spinal cord,in living fish were visible by naked eye.Compared with common crucian carp,the main chromatophores in the transparent fish was xanthophore,loss of iridophore,and the number of melanophore was reduced.The process of microsporidia infection in transparent mutants can be directly visualized in vivo,and the dynamic,spatial pattern of pathogen invasion could be acquired in a real-time manner,superior to other conventional fish models.Conclusions The absence of iridophores underlies the transparent mutant of crucian carp histologically.The changes of internal organs in transparent fish can be observed directly,do not require anatomical or other delicate instruments.A series of dynamic data are likely to be observed from a single transparent fish,therefore,it is expected to be widely used in life science studies.