Microglia/Macrophages Responses to Kainate-Induced Injury in the Rat Retina
Resource
NEUROSCIENCE RESEARCH v.54 n.3 pp.202-212
Journal
NEUROSCIENCE RESEARCH
Journal Volume
v.54
Journal Issue
n.3
Pages
202-212
Date Issued
2006
Date
2006
Author(s)
WU, CHING-HSIANG
CHIEN, HSIUNG-FEI
Abstract
The present study was aimed to elucidate how retinal microglia/ macrophages would respond to neuronal death after intravitreal kainate injection. An increased expression of the complement receptor type 3 (CR3) andan induction of the major histocompatibility complex (MHC) class II and ED-1 antigens were mainly observed in the inner retina after kainate injection. Prominent cell death revealed by Fluoro Jade B (FJB) staining and ultrastructural examination appeared at the inner border of the inner nuclear layer (INL ) at 1 day post-injection. Interestingly, some immunoreactive cells appeared at the outer segment of photoreceptor layer (OSPRL) at different time intervals. Our quantitative analysis further showed that CR3 immunoreactivity was drastically increased peaking at 7 days but subsided thereafter. MHC class II and ED-1 immunoreactivities showed a moderate but steady increase peaking at 3 days and declined thereafter. Double labeling study further revealed that retinal microglia/ macrophages expressed concurrently CR3 and ED-1 antigens (OX-42(+)/ED-1( + )) or MHC class II molecules (OX-42(+)/OX-6(+)) and remained branched in shape at early stage of kainate challenge. By electron microscopy, microglia/macrophages with CR3 immunoreactivity displayed abundant cytoplasm containing a few vesicles and phagosomes. Other cells ultrastructurally similar to Muller cells or astrocytes could also engulf exogenous substances. In conclusion, retinal microglia/macrophages responded vigorously to kainate-induced neuronal cell death that may also trigger the recruitment of macrophages from neighboring tissues and induce the phagocytotic activity of cells other than retinal microglia/ macrophages. (c) 2005 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.
Subjects
intravitreal injection
kainate
microglia/macrophages
retina
Type
journal article