Abstract
Abstract: :
Purpose: Previous studies have used hematoxylin and eosin to demonstrate that inflammatory cells infiltrate the cornea at around 24 hours after PRK. The purpose of this study was to characterize specific inflammatory cell types that infiltrate the cornea at 24 and 72 hours after PRK and LASIK. Methods: New Zealand White rabbits had low PRK (-4.5 diopters), high PRK (-9.0 diopters), or high LASIK (-9.0 diopters) with the VisX S3 laser. At 24 and 72 hours after surgery corneas were fixed with 4% phosphate buffered paraformaldehyde for 6 hours at 4? C and processed for cryomicrotomy. Immunocytochemistry was performed on 50 µm free-floating sections with T2008X (Research Diagnostics; binds macrophages and macrophage-like cell lines, monocytes, Kupffer cells, Langerhans cells, and microglia) and anti-RLA-DR (PharMingen; binds lymphocytes and macrophages). Specimens were immersed in 1 mM copper sulfate in 50 mM ammonium acetate at pH 5.0 for 30 minutes to quench auto-fluorescence in the corneal stroma and in granulocytes. The sections were then glycerol mounted on glass slides, and microscopy was performed with the Zeiss LSM 510 MP confocal microscope system. The specimens were optically sectioned to create digital image stacks that were computationally projected to produce 3 dimensional views. Results: Large numbers of T2008X-positive and RLA-DR-positive cells infiltrate the anterior stroma by 24 hours after low or high PRK compared with control corneas. Very small numbers of cells are noted following high LASIK. Many of these cells disappear by 72 hours after PRK. The cells that infiltrate are complex. Some cells label with T2008X or RLA-DR. Some label with both antibodies. Large numbers of RLA-DR-positive dendritic-shaped cells infiltrate the posterior stroma in some PRK corneas. Conclusion: Large numbers of macrophages/monocytes and lymphocytes infiltrate the anterior stroma between 24 and 72 hours after PRK. Inflammatory cell infiltration is very low in eyes that have normal LASIK. Inflammatory cells are likely attracted to the stroma by epithelial-keratocyte-inflammatory cell cytokine and chemokine-mediated interactions (IOVS 2001;42:2795-2803).
Keywords: 548 refractive surgery: LASIK • 552 refractive surgery: PRK • 631 wound healing