Endogenous Glucocorticoids Participate in Retinal Degeneration During Continuous Illumination

Abstract

Continuous illumination (CI) induces an oxidative stress of the retina which is involved in light-induced retinal degeneration (LIRD). As the increase of glucocorticoids (GC) could also collaborate in the damage, adrenalectomized (ADX) and sham-operated rats (control, CTL) were submitted to CI, and their eyes were studied at light and electron microscopic levels. After CI, ADX retinas were significantly thicker than CTL retinas. Retinal alterations appeared earlier and were severer in CTL than in ADX retinas. Corticosterone levels increased gradually in the sera of CTL rats along CI. These results suggest that adrenalectomy attenuates LIRD, supporting the hypothesis.

New insights in the male anatomy, spermatophore formation, and sperm structure in Atyidae: The red cherry shrimp Neocaridina davidi

“…Thin and ultrathin sections (thickness 0.5–1 μm) were obtained with a Reichert‐Jung ultramicrotome (model Ultracut E). Thin sections were stained with 1% toluidine blue (López et al., ), and ultrathin sections were contrasted with uranyl acetate and lead citrate (Reynolds, ). The samples were analyzed and photographed using a Zeiss EM 109T transmission electron microscope operated at 80 kV.…”

“…Thin and ultrathin sections (thickness 0.5-1 μm) were obtained with a Reichert-Jung ultramicrotome (model Ultracut E). Thin sections were stained with 1% toluidine blue (López et al, 2008), and ultrathin sections were contrasted with uranyl acetate and lead citrate (Reynolds, 1963). The Paired testes were positioned on the dorsal to dorsolateral side of the cephalothorax, without connection between them, above the hepatopancreas and below the heart, and extending to the third abdominal somite.…”

Ultrastructure of the scolex of Orygmatobothrium schmittii (Cestoda: Phyllobothriidea)

“…Samples were washed in buffered phosphate and postfixed for 1 hr in 1% OsO4 in the same buffer. The specimens were dehydrated and embedded in Durcupan resin (López et al, ). Semithin sections (thickness 0.5–1 μm) were obtained with a Reichert‐Jung ultramicrotome (model Ultracut E) and were stained with 1% Toluidine blue (López et al, ) and Sudan black for lipid detection, or Coomassie brillant blue for protein detection.…”

Adenosine A1 receptor: A neuroprotective target in light induced retinal degeneration

“…The main hallmarks of the LIRD model are similar to some of those detected in human AMD, juvenile macular degeneration or retinitis pigmentosa. The degenerative process starts in the outer retina as continuous illumination (CI) produces photoreceptor (PH) degeneration, apoptosis in the outer nuclear layer (ONL), increased phagocytosis by the retinal pigment epithelium (RPE) and synaptic degeneration in the outer plexiform layer (OPL) [ 7 , 13 – 17 ]. Conversely, in other degenerative diseases such as diabetic retinopathy, retinopathy of prematurity, glaucoma, and ischemia, degeneration starts in the inner retina and affects primarily to inner nuclear layer, ganglion cell layer and optic nerves [ 18 – 20 ].…”

“…In our hands, treating albino rats (Sprague Dawley) with white light (12 klux) produces a peak of NO after one day of continuous illumination [ 10 ], an increase of glucocorticoids, a great number of apoptotic nuclei in the outer nuclear layer after 2 days of continuous illumination [ 7 ], and the complete loss of photoreceptors after 7 days of continuous illumination [ 17 ].…”