Abstract
Purpose:
To study the detailed cellular and molecular changes in mouse sclera cells when subjected to experimental glaucoma.
Methods:
We peformed experimental bead-injection glaucoma on three strains of mice that were sacrificed at 3 days, 1, 3 and 6 weeks. Liquid chromatography coupled with tandem mass spectrometry was used to quantify scleral protein expression. Immunoblots of sclera protein samples were also analyzed with specific antibodies against those proteins quantified in proteomic studies of the same time points. For histological studies of scleral changes, the proportion of proliferating scleral fibroblasts was quantified by Ki67 and DAPI labeling was done on wholemount samples as well as qualitative analysis labeling with α-smooth muscle actin (α-SMA), phalloidin, actinin, thrombospondins (TSP) 1 and 2, integrin α2β1, paxillin, smad2, smad3, and vimentin.
Results:
Integrin-linked kinase signaling and actin cytoskeleton signaling pathways were increased in proteomic studies of scleras analyzed at 1 and 6 weeks after glaucoma. Counts of Ki67 positive sclera cells showed that peripapillary scleral had more fibroblasts than anterior sclera (p = 0.001, n = 217, multivariable regression models). After 1 week exposure to glaucoma there was a 6 fold increase in proliferating fibroblasts and a 3 fold rise at 3 and 6 weeks ( p = 0.0005, univariate regression). Qualitative differences in labeling for α-SMA, α-actinin, TSP1, 2, integrin α2β1, paxillin and vimentin in B6 and CD1 mice were detectable 3 days post bead injection. After 6 weeks exposure to glaucoma labeling declined to control levels.
Conclusions:
The effect of experimental mouse glaucoma increases cell division, promotes myofibroblastic transition, and show increases in actin cytoskeleton and integrin-related signaling. Axial elongating effects of experimental glaucoma are contrary to those found in axial elongation of myopic eyes.
Keywords: 708 sclera •
654 proliferation •
519 extracellular matrix