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Form‐deprivation myopia in the guinea pig: scleral myofibroblasts and biomechanics
Author(s) -
PHILLIPS JR,
BACKHOUSE S
Publication year - 2008
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2008.403.x
Subject(s) - myofibroblast , sclera , ophthalmology , vitreous chamber , medicine , dapi , anatomy , guinea pig , visual acuity , refractive error , pathology , staining , endocrinology , fibrosis
Purpose To investigate the effect of induced myopia on cell populations and biomechanical properties of the sclera. Methods Week‐old guinea pigs (n = 29) were monocularly deprived (MD) of form vision for 14 days. Total cells and myofibroblast (contractile) cells were visualized using DAPI and α‐smooth muscle actin (α‐SMA) antibodies respectively in 20 µm thick scleral sections. Ocular biomechanics were investigated by raising the IOP to 50 mmHg for one hour in anaesthetized animals. Ultrasound biometry measures were made before, during (every 10 min) and after raising the IOP. Results As expected, MD eyes developed significant axial myopia. Generally, MD had no effect on total cell number or myofibroblast number compared to control or normal eyes. However, in MD eyes a significant decrease in total cell number was observed between the optic nerve and 10° nasal (equivalent to human temporal myopic crescent). Overall, myofibroblasts accounted for 63.67 ± 1.65% of scleral cells (mean ± SEM: three groups combined; n = 30 eyes). On increasing IOP, there was significant elastic expansion of the vitreous chamber depth (VCD) in deprived and control eyes but not in normal eyes. The VCD creep response to increased IOP stabilized at equivalent lengths to MD and control eyes. Conclusion A high proportion of scleral cells are myofibroblasts, but cell number is unaffected by MD. The biomechanical response of MD eyes differs from normal eyes, suggesting that something other than myofibroblast cell number controls axial length.