Abstract
Purpose: :
To evaluate the influence of diet (atherogenic high–fat versus regular rodent diet) on the development of corneal neovascularization and intraocular inflammation in a corneal neovascularization animal model.
Methods: :
Two groups of 4 and 8 months old C57Bl/6 mice (n=20/group) were fed for 4 months either with a regular rodent diet (ND; n=10/group) or an atherogenic high–fat rodent diet (HD; n=10/group). The right eye of each mouse was subsequently treated 5–times (every other day) with argon laser (laser settings: 488 nm, spot size 50 µm, power 50 mW, duration 20 msec) as a model of corneal injury. The untreated left eyes served as controls. The eyes were examined daily for any signs of corneal neovascularization or anterior chamber reaction. All mice were euthanized six weeks after the initial laser treatment and the corneas were evaluated by light and electron microscopy. Immunohistochemistry was performed using antibodies against vascular endothelium (CD31) and macrophages (F4/80).
Results: :
Corneal neovascularization was present in all four treatment groups. Blood vessels arose from the limbal region and occurred between day 3 and 7 after laser treatment in mice fed with ND and 7 days after the initial laser application in mice fed with HD. Corneal neovascularization was found in high frequency in eyes of young (4 months old) mice and animals fed with ND [94.4% (ND, 4 mo) and 80% (ND, 8mo)]. Mice fed with HD demonstrated corneal neovascularization in 20% (4 mo) and 5% (8 mo). F4/80 staining inflammatory cells in the corneal stroma were more common in mice fed ND in comparison to mice fed under HD. Signs of intraocular inflammation were only present in mice fed with ND [33.3% (4 mo) and 16.4% (8 mo)].
Conclusions: :
Our animal model of corneal neovascularization suggests that high–fat diet and aging have an effect on the immune response resulting in a lower degree of intraocular inflammation and corneal neovascularization. The presence of polyunsaturated fatty acids and omega–3 fatty acids might be responsible for the decreased immune response including cytokine expression.
Keywords: neovascularization • cornea: basic science • lipids