Three-dimensional organization of primary lens fiber cells

PURPOSE. TO visualize the three-dimensional organization of primary lens fi ber cells. METHODS. The gene for Green Fluorescent Protein (GFP) was introduced into t he lens vesicle using two different vector systems: a replication deficient adenovirus or an expression plasmid. Injected embryos were allowed to deve lop for several days and then were examined by confocal microscopy. RESULTS. Injection of either vector resulted in GFP expression in primary f iber cells. GFP-expressing cells were heterogeneous in shape and length. So me regions of the fibers were varicose, with diameters >10 mu m; regions be tween the varicosities were often extremely thin, with diameters of <2 mu m . No differences in the morphologies of GFP-expressing cells were noted bet ween adeno-virus- and plasmid-injected lenses, suggesting that the irregula r, undulating, appearance of the primary fibers was not the result of viral infection. Three-dimensional reconstruction of primary fiber cells reveale d that, by EG, the posterior tips of the fibers had detached from the lens capsule. The anterior fiber tips remained in contact with the overlying epi thelium for 1 to 2 additional days, demonstrating that the formation of the anterior and posterior sutures was asynchronous. CONCLUSIONS. The three-dimensional cellular organization of GFP-expressing cells is consistent with previous analyses of fiber cell morphology in the embryonic nucleus of adult human and bovine lenses. The present data confir m that the disorganized appearance of primary fiber cells observed in adult lenses is largely a reflection of developmental processes rather than a co nsequence of aging.