GAP JUNCTION STRUCTURES AND DISTRIBUTION PATTERNS OF IMMUNOREACTIVE CONNEXIN-46 AND CONNEXIN-50 IN LENS REGROWTHS OF RHESUS-MONKEYS

Gap junction structures and distribution patterns of immunoreactive co nnexin46 (Cx46) and connexin 50 (Cx50) in normal lenses and lens regro wths of rhesus monkeys were studied using electron microscopy and immu nofluorescence double-labeling. Lens regrowths were collected from aph akic eyes of young monkeys whose natural lenses had been surgically re moved 11-34 months earlier to simulate monocular congenital cataract s urgery in human infants. Approximately 90% of the lens regrowths exami ned was in the form of a doughnut-shaped Soemmerring's ring located be hind the iris. The lens regrowth consisted of lens epithelium and lens fibers enclosed within hypertrophied capsular material. The superfici al equatorial region usually contained nucleated young fibers of norma l appearance, The other regions consisted of many swollen fibers. Gap junctions were readily observed between fiber cells of both normal and swollen configuration in the lens regrowth. In superficial fibers, ga p junctions were not associated with cytoskeletal components. In the i ntermediate and the deeper cortical regions, actin filament bundles we re found specifically associated with gap junctions along both of thei r cytoplasmic surfaces. An immunofluorescence double-labeling study sh owed that Cx46 and Cx50 were labeled in the same gap junctions in both superficial and deeper cortical fibers of the normal lens. In contras t, in the lens regrowth strong co-labeling of Cx46 and Cx50 was only o bserved in the superficial fibers. The labeling for Cx50 was very weak or absent in the deeper cortex, whereas the strong labeling for Cx46 persisted throughout the major portion of the deeper cortex. The label ing for Cx46 finally disappeared in the much deeper cortex. This study shows that (1) the same distribution pattern of actin bundle/gap junc tion association found in normal lenses is seen in the lens regrowth, and (2) the immunoreactive distribution of Cx46 and Cx50 differ in the lens regrowths as compared with those in the normal lenses of rhesus monieys. (C) 1996 Academic Press Limited