Microglial response to light-induced photoreceptor degeneration in the mouse retina.
The microglial response elicited by degeneration of retinal photoreceptor cells was characterized in BALB/c mice exposed to bright light for 7 hours and then kept in complete darkness for survival times ranging from 0 hours to 10 days. Photodegeneration resulted in extensive cell death in the retina, mainly in the outer nuclear layer (ONL), where the photoreceptor nuclei are located. Specific immunolabeling of microglial cells with anti-CD11b, anti-CD45, anti-F4/80, anti-SRA, and anti-CD68 antibodies revealed that microglial cells were activated in light-exposed retinas. They migrated to the ONL, changed their morphology, becoming rounded cells with short and thick processes, and, finally, showed immunophenotypic changes. Specifically, retinal microglia began to strongly express antigens recognized by anti-CD11b, anti-CD45, and anti-F4/80, coincident with cell degeneration. In contrast, upregulation of the antigen recognized by anti-SRA was not detected by immunocytochemistry until 6 hours after light exposure. Differences were also observed at 10 days after light exposure: CD11b, CD45, and F4/80 continued to be strongly expressed in retinal microglia, whereas the expression of CD68 and SRA had decreased to near-normal values. Therefore, microglia did not return to their original state after photodegeneration and continued to show a degree of activation. The accumulation of activated microglial cells in affected regions simultaneously with photoreceptor degeneration suggests that they play some role in photodegeneration.
Santos
Ana M
AM
Departamento de Biología Celular, Facultad de Ciencias, Universidad de Granada, E-18071 Granada, Spain.
Martín-Oliva
David
D
Ferrer-Martín
Rosa M
RM
Tassi
Mohamed
M
Calvente
Ruth
R
Sierra
Ana
A
Carrasco
Maria-Carmen
MC
Marín-Teva
José L
JL
Navascués
Julio
J
Cuadros
Miguel A
MA
D000818:Animals; D000918:Antibody Specificity / Q000276:immunology; D000954:Antigens, Surface / Q000032:analysis / Q000378:metabolism; D015415:Biomarkers / Q000032:analysis / Q000378:metabolism; D002465:Cell Movement / Q000276:immunology; D048430:Cell Shape; D002633:Chemotaxis / Q000276:immunology; D003624:Darkness; D004195:Disease Models, Animal; D005911:Gliosis / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D007150:Immunohistochemistry; D016130:Immunophenotyping; D008027:Light / Q000009:adverse effects*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D017628:Microglia / Q000502:physiology* / Q000528:radiation effects*; D009410:Nerve Degeneration / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D012162:Retinal Degeneration / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*
D000954:Antigens, Surface; D015415:Biomarkers