Ultrastructure of respiratory cilia of WIC-Hyd male rats. An animal model for human immotile cilia syndrome.

The WIC-Hyd rat is a mutant from the Csk: Wistar-Imamichi rat, with spontaneous hydrocephalus. In male rats, the hydrocephalus is severe and about one half of hydrocephalic male littermates possess situs inversus totalis. Ependymal cilia in these animals are immotile, and this defect is regarded as a mechanical cause of hydrocephalus. This paper presents the ultrastructural features of respiratory cilia in these rats in comparison with those in human immotile cilia syndrome. The respiratory cilia in these rats also are immotile and the dynein arms are missing, as in human cases. Previously only eight dogs with immotile cilia syndrome and a mutant hydrocephalic-polydactyl mouse were reported with respect to these phenomena. However the WIC-Hyd rat is the first useful animal model for human immotile cilia syndrome, and further studies may serve to clarify the genetic background of this condition.