INVESTIGADORES
DORFMAN Damian
artículos
Título:
Effect of retinal ischemia on the non-image forming visual system
Autor/es:
GONZÁLEZ FLEITAS MF; BORDONE M; ROSENSTEIN RE; DORFMAN D
Revista:
CHRONOBIOLOGY INTERNATIONAL
Editorial:
TAYLOR & FRANCIS INC
Referencias:
Lugar: Oxford; Año: 2014
ISSN:
0742-0528
Resumen:
Retinal ischemic injury is an important cause of visual impairment. The
loss of retinal ganglion cells (RGCs) is a key sign of retinal ischemic
damage. A subset of RGCs expressing the photopigment melanopsin (mRGCs)
regulates non-image-forming visual functions such as the pupillary light
reflex (PLR), and circadian rhythms. We studied the effect of retinal
ischemia on mRGCs and the non-image-forming visual system function. For
this purpose, transient ischemia was induced by raising intraocular
pressure to 120 mm Hg for 40 min followed by retinal reperfusion by
restoring normal pressure. At 4 weeks post-treatment, animals were
subjected to electroretinography and histological analysis. Ischemia
induced a significant retinal dysfunction and histological alterations.
At this time point, a significant decrease in the number of Brn3a(+)
RGCs and in the anterograde transport from the retina to the superior
colliculus and lateral geniculate nucleus was observed, whereas no
differences in the number of mRGCs, melanopsin levels, and retinal
projections to the suprachiasmatic nuclei and the olivary pretectal
nucleus were detected. At low light intensity, a decrease in pupil
constriction was observed in intact eyes contralateral to ischemic eyes,
whereas at high light intensity, retinal ischemia did not affect the
consensual PLR. Animals with ischemia in both eyes showed a conserved
locomotor activity rhythm and a photoentrainment rate which did not
differ from control animals. These results suggest that the non-image
forming visual system was protected against retinal ischemic damage.