Abstract
Purpose:
To investigate lens regeneration in terms of cell growth, cell differentiation and cell polarity in a rodent model.
Methods:
An extracapsular crystalline lens extraction was undertaken to preserve the lens capsular bag and anterior lens epithelium on the right eye of 60 Sprague-Dawley rats. Contralateral, unoperated eyes served as controls. Cell proliferation was tracked using EdU, which was injected intra-peritoneally before sacrifice on 0, 1, 2, 3, 7, 10, 15, 30 and 50 days postoperatively. EdU labelled cells were detected by Click-iT labelling. The expression of beta-catenin, E-/N-cadherin, AQP0, ZO-1 and gama-tubulin was monitored by confocal immunofluorescence light microscopy using a Leica SP5 system.
Results:
Newly regenerated lenses were optically clear and the capsular bag filled steadily with cellular material post-extracapsular cataract surgery. A focal opacity was usually observed at the capsulotomy site. A monolayer of cells lined both the anterior and posterior capsule at the early stage of lens regeneration. A burst of cell proliferation occurred in the lens cells on day 1 after surgery, but then decreased rapidly. There was extensive cell reorganisation within the capsular bag. By day 7, epithelial cells at the lens periphery were starting to differentiate, which was followed by changes in the cells only on the posterior capsule. In contrast, epithelial cells on the anterior capsule surface continue to proliferate. The reorganisation of the cell layers during these early stages of lens regeneration adheres to a programme that results in the re-establishment of central, germinative (GZ) and transitional zones (TZ) by day 30 postoperatively.
Conclusions:
Lens regeneration involves both temporal and spatial cues to re-establish the cell compartments that typify the unoperated mammalian lens.
Keywords: 687 regeneration