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Astrocytic responses in the lateral geniculate nucleus of monkeys with experimental glaucoma

Authors

  • Yi Dai,

    1. Department of Ophthalmology and Vision Science, EYE & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China
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  • Xinghuai Sun,

    1. Department of Ophthalmology and Vision Science, EYE & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China
    2. Institute of Brain Science, State Key Laboratory for Medical Neurobiology, Fudan University, Shanghai, China
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  • Xiaobo Yu,

    1. Department of Ophthalmology and Vision Science, EYE & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China
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  • Wenyi Guo,

    1. Department of Ophthalmology and Vision Science, EYE & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China
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  • Daoyi Yu

    1. Center of Ophthalmology and Vision Science, The University of Western Australia, Nedlands, WA 6009, Australia
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Address communications to:
X. Sun
Tel.: (86) 21 6437 7134 (ext. 818)
Fax: (86) 21 6437 7151
e-mail: xhsun@shmu.edu.cn

Abstract

Objective  To investigate the responses of lateral geniculate nucleus (LGN) astrocytes to experimental glaucoma in monkeys.

Animal studied  Rhesus monkeys (Macaca mulatta).

Procedures  Unilateral chronic elevation of intraocular pressure (IOP) was induced in six rhesus monkeys by laser photocoagulation of the trabecular meshwork. Four normal monkeys were used as controls. Immunohistochemistry with antibodies to glial fibrillary acidic protein (GFAP), S100β and parvalbumin was used to specifically label astrocytes and neurons in the LGN. The relative immunointensity (RI) of GFAP was defined as the ratio of intensity between each region of interest to a reference field and compared between the experimental and control groups as a function of percentage optic nerve fiber loss. Ultrastructural changes of LGN astrocytes were examined by transmission electron microscopy.

Results  An increase in GFAP and S100β immunoreactivity was observed in the LGN layers receiving projections from the experimental glaucoma eyes. Quantitative analysis revealed that the RI of GFAP in both the magnocellular and parvocellular layers connected to the glaucomatous eyes increased in a linear fashion with increasing optic nerve fiber loss. Compared to controls, the RI of GFAP was also moderately elevated in LGN layers connected to the fellow nonglaucomatous eyes. Ultrastructurally, accumulation of glial filaments that occurred throughout the perikaryon and extended into the process in reactive astrocytes was observed in LGN layers of glaucomatous monkeys.

Conclusions  Reactive astrogliosis occurs in the magnocellular and parvocellular LGN layers of monkeys with unilateral glaucoma. Astrocytes may play an important role in the regulation of LGN microenvironment in glaucoma.

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