Observation of 100 nm periodic fibrils in mouse corneal stroma by cryoultramicrotomy.

We observed mouse corneal stroma after treatment with 20 mM adenosine 5'-triphosphate (ATP), thin-sectioned by cryoultramicrotomy, with a transmission electron microscope. A wide array of 100 nm periodic fibrils (100 nm PFs) was observed among D-periodic collagen fibrils. By indirect immuno-cryoultramicrotomy with anti-type VI collagen antibody, immunogold particles were located on 100 nm PFs, indicating that 100 nm PFs were composed of type VI collagen. Cryoultramicrotomy is useful for studying the ultrastructure of the extracellular matrix of the corneal stroma.