Quantitation of corneal fibril diameters from bony fish using low temperature preparative methods

Low-temperature dehydration and embedding techniques have been used to preserve the transverse structure of corneal collagen fibrils from nine bony fish. The diameters measured all lie close to a value of 25.5 nm, in contrast to the smaller (and more diverse) diameters measured from “conventionally” prepared controls. The results are consistent with our earlier studies on the corneas from mammals, amphibians, birds, reptiles, and cartilaginous and bony fish which showed that the collagen fibrils from the bony fish were significantly smaller than those from animals of the other vertebrate classes. Thus, on the basis of the enhanced ability of the low-temperature preparative techniques to preserve collagen fibril structure the “in vivo” corneal collagen fibril diameters have been revised from 17 to 25.5 nm for bony fish (this work) and from 25 to 36 nm for all other classes of vertebrates (our previous work).