COMPARISON OF HUMAN LENS EPITHELIAL-CELLS IN SITU AND IN VITRO IN RELATION TO AGING - ULTRASTRUCTURAL-STUDY

As compared with embryonic cells in situ, cells in lenses of individuals over 48 yr old possessed fewer cytoplasmic organelles, a denser cytoplasmic matrix composed of granular and filamentous material, and masses of condensed chromatin. Single cilia were noted in the equatorial cells of both adult and embryonic lenses. The embryonic lens capsule was laminated, the adult capsule was usually homogenous. Features related to pathological conditions in the adult epithelium were: conspicuous cytoplasmic microfilaments, degenerated cells, and atypical granular and filamentous structures in the capsule. Cells derived from adult lenses in 4 wk primary cultures were indistinguishable from embryonic cells; they showed increases in their content of mitochondria, polysomes and nucleoli. Aggregated cells in 1-14 wk primary cultures, or subcultures, of adult cells were structurally heterogeneous, possessing varied amounts of cytoplasmic organelles, microfilaments and granular material. Masses of intercellular material were present in the aggregates. Features related to aging in culture were: polymorphic nuclei, vacuolated cytoplasm and large, complex lysosomal bodies. Cultured cells from adult lenses probably initially dedifferentiated and, with time, reverted to parental cell type if they were associated in groups.