Morphology and organization of posterior fiber ends duringmigration

[摘要] Purpose: To characterize structural parameters of the basal membranecomplex (BMC) and to determine the arrangement and organization ofposterior fiber ends during elongation/migration in lenses with branchedsutures.Methods: Lenses from normal, juvenile (4-6 week old) Sprague-Dawleyrats (n=16) were utilized. Posterior fiber ends were assessed on bothwhole mounts of lens capsules and on decapsulated lenses. The size,shape and organization of migrating fiber ends was assessed by scanningelectron microscopy (SEM) and laser scanning confocal microscopy (LSCM)along the entire posterior surface. The area of the BMC was measuredusing image analysis software and subjected to statistical analysis.Results: Posterior fiber ends had a characteristic regionalarrangement during elongation and migration along the capsule. Theseregions were termed the equatorial, the lateral-posterior (posteriorfrom the equator to within 150 μm of the sutures), the peri-sutural(150 μm surrounding the sutures), and the sutural. The area of fiberends (seen by SEM) was compared to the area of fluorescent F-actinprofiles (seen by LSCM). There was no significant difference (p=0.324)between the average basal end area (40.21 μm2) and the averagearea of F-actin profiles (40.65 μm2). The average fiber endarea in the lateral-posterior, peri-sutural, and sutural regions was63.19 μm2, 71.95 μm2, and 25.75 μm2,respectively. In the equatorial region, footprints were aligned in rowsoriented toward the posterior pole, consistent with the arrangement ofstraight, meridional rows. Initially, fiber ends within thelateral-posterior region were arranged in short irregular rows havingvariable orientation with respect to the posterior pole. The remainderof these ends were randomly arranged. In the peri-sutural region, fiberends approaching suture branches were aligned in short rows oriented atangles to the posterior pole. At the sutures, fiber ends appeared tobecome rounded, presumably during detachment from the capsule.Conclusions: The results confirm that F-actin profiles delineate theBMC of posterior fiber ends. Furthermore, the average area, shape andarrangement of fiber ends varies in a predictable pattern duringmigration. The data suggests that elongating fiber ends follow definedmigration patterns along the posterior capsule to their suturaldestinations. This controlled process is crucial to the formation ofordered suture patterns, thereby minimizing their adverse effects onlens optical quality.

[学科分类] 生物化学/生物物理