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1.
Invest Ophthalmol Vis Sci ; 47(7): 3156-63, 2006 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16799063

RESUMO

PURPOSE: The present study was performed to investigate the effect of crocin on blue light- and white light-induced rod and cone death in primary retinal cell cultures. METHODS: Primary retinal cell cultures were prepared from primate and bovine retinas. Fifteen-day-old cultures were exposed to blue actinic light or to white fluorescent light for 24 hours. Cultures were treated by the addition of different concentrations of crocin for 24 hours before light exposure or for 8 hours after light exposure. Cultures kept in the dark were used as controls. Green nucleic acid stain assay was used to evaluate cell death. Rods and cones were immunolabeled with specific antibodies and counted. TUNEL labeling was used to detect fragmented DNA in fixed cells after light exposure. RESULTS: Primary retinal cell cultures contained a mixture of retinal cells enriched in photoreceptors, bipolar cells, and Müller cells. Twenty-four-hour exposure to blue and white light induced death in 70% to 80% of the photoreceptors in bovine and primate retinal cell cultures. Crocin protected the photoreceptors against blue light- or white light-mediated damage in a concentration-dependent manner with an EC50 of approximately 30 microM. TUNEL assays confirmed that crocin protected photoreceptors from light damage. CONCLUSIONS: These results show that blue and white light selectively induce rod and cone cell death in an in vitro model. Crocin protects retinal photoreceptors against light-induced cell death.


Assuntos
Carotenoides/farmacologia , Luz/efeitos adversos , Células Fotorreceptoras de Vertebrados/efeitos da radiação , Extratos Vegetais/farmacologia , Lesões Experimentais por Radiação/prevenção & controle , Degeneração Retiniana/prevenção & controle , Animais , Bovinos , Contagem de Células , Técnicas de Cultura de Células , Morte Celular/efeitos dos fármacos , Morte Celular/efeitos da radiação , Crocus , Relação Dose-Resposta a Droga , Flores , Técnica Indireta de Fluorescência para Anticorpo , Marcação In Situ das Extremidades Cortadas , Macaca fascicularis , Células Fotorreceptoras de Vertebrados/efeitos dos fármacos , Lesões Experimentais por Radiação/etiologia , Degeneração Retiniana/etiologia
2.
Exp Eye Res ; 85(1): 154-65, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17544396

RESUMO

The present study was performed to investigate the effect of flavonols, namely myricetin and structurally related quercetin and kaempferol against A2E and blue light-induced photoreceptors death in primary retinal cell cultures. Primary retinal cell cultures were prepared from bovine retinas. Fourteen-day-old cultures were pretreated with different concentrations of myricetin, quercetin, kaempferol (1-40 microM) for 24 h, then treated with 30 microM of A2E or exposed to blue-actinic light for 20 h. Green nucleic acid stain assay was used to evaluate cell death. Photoreceptor and bipolar cells were immunolabeled with specific antibodies and were counted using automated microscope imaging and image-based cell counting software. Twenty hours exposure to blue light induced approximately 75% death of photoreceptors in bovine retinal cell cultures. Myricetin protected 100% of photoreceptors against blue-light-mediated damage with an EC(50) of 9+/-0.7 microM. Quercetin resulted in a maximum of 15% protection against light damage, and kaempferol was inactive. A2E induced photoreceptor and bipolar cell death in a concentration-dependent manner with EC(50) of 25 microM for photoreceptors and 31 microM for bipolar cells. Myricetin, quercetin and kaempferol protected against A2E-induced photoreceptors and bipolar cells death with EC(50) values of 2+/-0.3 microM, 2+/-0.3 microM, 5+/-0.09 microM and 0.8+/-0.07 microM, 0.44+/-0.06 microM, 1+/-0.4 microM, respectively. Caspase-3 inhibitor (Z-DEVD-fmk) protected 42% photoreceptors and 57% bipolar cells from A2E toxicity. In contrast, this inhibitor had no effect against light-induced photoreceptor damage. Despite the poor activity of quercetin and the inactivity of kaempferol against blue light, myricetin, quercetin and kaempferol exhibited approximately 100% protection against A2E toxicity. This suggests that light- and A2E-induced cell deaths are mediated through different pathways. These results suggest that myricetin functions as potent and effective neuroprotective agent for photoreceptor cells against A2E and light damage.


Assuntos
Apoptose/efeitos dos fármacos , Flavonoides/farmacologia , Flavonóis/farmacologia , Fármacos Neuroprotetores/farmacologia , Células Fotorreceptoras de Vertebrados/efeitos dos fármacos , Compostos de Piridínio/antagonistas & inibidores , Retinoides/antagonistas & inibidores , Animais , Inibidores de Caspase , Bovinos , Contagem de Células , Células Cultivadas , Inibidores de Cisteína Proteinase/farmacologia , Imuno-Histoquímica/métodos , Quempferóis/farmacologia , Luz , Oligopeptídeos/farmacologia , Estresse Oxidativo/fisiologia , Células Fotorreceptoras de Vertebrados/citologia , Compostos de Piridínio/farmacologia , Quercetina/farmacologia , Retinoides/farmacologia
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