A short period of dark-adaptation is sufficient to generate light-induced photoreceptor degeneration in pigmented zebrafish.

Light-induced retinal degeneration (LIRD) models are used to recapitulate the pathologies of retinal diseases that affect photoreceptors. Current LIRD models use a dark-adaptation period of 7-14 days followed by high-intensity light exposure. The purpose of this study was to determine whether photoreceptor damage and death would occur in pigmented zebrafish using a short period of dark-adaptation. Zebrafish were dark-adapted for 24 h and then exposed to constant high-intensity light for 48 h. Immunohistochemical analysis was performed on vertical retinal sections to assess damage and apoptosis. Photoreceptors exhibited structural damage, apoptosis, and cell loss after 24 and 48 h of light exposure as previously reported in studies using 7-14 day dark-adaption. Also, photoreceptors lost following light damage were regenerated after 28 days. These results suggest that a short period of dark-adaptation is sufficient for a LIRD model in pigmented zebrafish.

The omega-3 fatty acid docosahexaenoic acid attenuates organic dust-induced airway inflammation.

Workers exposed to organic dusts from concentrated animal feeding operations (CAFOs) are at risk for developing airway inflammatory diseases. Available preventative and therapeutic measures for alleviating dust-induced lung disease are inadequate. Because omega-3 fatty acids can mitigate inflammatory processes, we aimed to determine whether nutritional supplementation with the omega-3 fatty acid docosahexaenoic acid (DHA) could reduce the airway inflammatory consequences of exposures to organic dust. Aqueous extracts of organic dusts from swine CAFOs (ODE) were utilized. In DHA-pretreated human bronchial epithelial cells, lung fibroblasts, monocyte cell cultures, and precision-cut murine lung slices, we found that DHA pretreatment dose-dependently decreased ODE-induced inflammatory cytokine production. To determine the in vivo significance of DHA, C57BL/6 mice were orally administered DHA for seven days prior to treatment with intranasal ODE or saline inhalations. Animals treated with 2 mg DHA demonstrated significant reductions in ODE-induced bronchial alveolar lavage neutrophil influx and pro-inflammatory cytokine/chemokine production compared to mice exposed to ODE alone. Collectively, these data demonstrate that DHA affects several lung cells to reduce the airway inflammatory response to organic dust exposures. Dietary supplementation with DHA may be an effective therapeutic strategy to reduce the airway inflammatory consequences in individuals exposed to agriculture dust environments.