Article
Analysis of C-FOS immunoreactivity in the visual system of adult rats after bilateral visual deafferentation
C-Fos-Expression im visuellen System der Ratte nach bilateraler visueller Deafferenzierung
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Published: | April 11, 2007 |
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Objective: Evaluation of acute and chronic changes of c-Fos expression patterns in the visual system of the rat after bilateral complete visual deafferentation.
Methods: In 20 adult male Lewis rats, the retro-orbital part of the optic nerve underwent bilateral surgical resection. 10 animals underwent c-Fos immunohistochemistry after 3 days and the other 10 animals after 3 weeks. The control group consisted of 10 animals, who did not undergo any surgical manipulation.
Results: C-Fos expression in the rat visual system underwent significant changes after acute and chronic bilateral complete visual deafferentation. Acute decrease of c-Fos level was observed in the ventral lateral geniculate nucleus, the intergeniculate leaflet, superficial gray layer of the superior colliculus and Layer IV and V of the primary visual cortex. After chronic deafferentation, c-Fos expression was decreased in the optic and deep layers of the superior colliculus and Layer VI of the primary visual cortex as well. No change of c-Fos expression was observed in the dorsal lateral geniculate nucleus and Layers I, II and III of the primary visual cortex.
Conclusions: Surgically induced complete secondary blindness does not lead to a uniform decrease of c-Fos levels in all subcortical and cortical brain regions related to vision. These findings provide important information concerning expression of the immediate early gene product c-Fos in secondary blind rodent models. They may serve as a baseline finding when electrical stimulation at various points of the visual system is performed with regard to the assessment of visual neuroprostheses in blind rodent models with the purpose of evaluating different stimulus parameters using c-Fos as a functional mapping tool.