Abstract
Purpose:
Ferrets have binocular vision unlike mice and rats, therefore ferrets are more suitable for analyzing the central visual pathway damage caused by glaucoma compared to mice and rats. Recent studies report that not only optic nerve but also the lateral geniculate nucleus (LGN) and visual cortex are damaged by glaucoma. The mechanism of the damage of the LGN was unknown closely because the ocular hypertension model was established only in monkey having binocular vision. We reported the ferret ocular hypertension model at ARVO 2012, 2013 and analyzed the damage of the central visual pathway in this model. We investigate the degeneration of neural glial cells in LGN using the ferret ocular hypertension model.
Methods:
We established ferret ocular hypertension model by injecting conjunctival cells into an anterior chamber. The LGN of ferret has the A and the A1 layer. The A layer is projected from contralateral eye, and the A1 layer is projected from ipsilateral eye. The LGN was removed and the horizontal section of the LGN was made after ferrets are sacrificed at 3 months after ocular hypertension. NeuN stains neurons, and glial fibrillary acidic protein (GFAP) stains astrocytes. NeuN and GFAP are used for analyzing the damage of the LGN of ferret ocular hypertension model. The number of neurons stained with NeuN and the staining intensity of GFAP in the bilateral A and A1 layers of square of 200 x 200 μm were compared with the right LGN and the left LGN using image-processing software (Image J).
Results:
The number of neuron stained with NeuN was 26.0 ± 3.8 (right), 17 ± 2.8 (left) in the A layer, and 17.9 ± 1.8 (right), 21.6 ± 2.1 (left) in the A1 layer (n=8, p<0.01). The number of neuron stained with NeuN was significantly decreased in the left A layer and the right A1 layer. The staining intensity of GFAP was 167.8 ± 11.0 (right), 177.4 ± 14.6 (left) in the A layer, and 175.8 ± 5.7 (right), 171.1 ± 5.6 (left) in the A1 layer (n=6, p<0.05). The staining intensity of GFAP was significantly increased in the left A layer and the right A1 layer. Decrease of the number of neuron and proliferation or activation of glial cells was detected in the LGN projected from right eye with ocular hypertension.
Conclusions:
It is possible to investigate the neuronal damage and glial reaction in the LGN induced by ocular hypertension in ferret with binocular vision.
Keywords: 554 immunohistochemistry •
540 glia •
568 intraocular pressure