vision/eye
• by 6 months of age, doxycycline-induced mice show discrete refractive foci in the fundus suggesting localized retinal degeneration
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• doxycycline-induced mice show abnormal retinal blood vessels starting at ~6 months of age
• fluorescein angiography revealed vascular leakage in regions of atrophy, with twisted major blood vessels, vascular beading, and increased branching and dilation of deeper blood vessels
• however, no signs of choroidal neovascularization are observed
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• at 9 months of age, one doxycycline-induced mouse showed subretinal hemorrhage between the photoreceptors and RPE
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• at 6 weeks of age, neonatally doxycycline-induced mice show extensive oxidative damage to DNA in the RPE, as shown by 8-OHdG staining; most immunoreactivity is in the cytoplasm although some oxidative damage is seen in nuclei
• increased oxidative stress results in accumulation of 4-HNE-modified proteins and superoxide in the RPE
• at 4 months of age, autofluorescence in the RPE is increased by >20-fold, and basal infoldings of the RPE appear disordered
• by 9 months, overall RPE thickness is increased by ~30% relative to that at 1 month of age, with most thickening detected in the superior region (>40%)
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• by 6 months, doxycycline-induced mice show hypopigmented areas and white spots reflected thinning of the retina
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• doxycycline-induced mice show slowly progressive retina atrophy during aging
• at 6 months or later, large regions of the RPE appear to be absent, with no intact ONL or photoreceptor layer
• by 9 months, disc membranes are more widely spaced, fragmented mitochondria accumulate along the basal surface of the RPE, membrane-filled vacuoles are seen in some areas, and apical microvilli are absent
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• in doxycycline-induced mice, the average ONL thickness in the posterior retina is reduced by 15% by 6 months and by 24% by 9 months
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• at 6 weeks of age, neonatally doxycycline-induced mice show increased accumulation of superoxide in the photoreceptor layer
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• by 9 months, photoreceptor inner segments are severely shortened in some regions
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• by 9 months, photoreceptor outer segments are severely shortened in some regions
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• by 9 months, the length of rod outer segments is increased in many areas of the retina, with gaps between disc membranes
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• at 4 months of age, neonatally doxycycline-induced mice show increased autofluorescence in the choroid
• at 6 months of age, the choroid layer shows distension and increased porosity
• by 9 months, the choroid appears less compact and more porous
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• at 4 months of age, doxycycline-induced mice show enlargement and disorganization of Bruch's membrane
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• doxycycline-induced mice show an age-related decline in the photopic b-wave amplitudes which becomes significant by 6 months
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• doxycycline-induced mice show an age-related decline in the scotopic a-wave and b-wave amplitudes which becomes significant by 6 months
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cellular
• at 2 months but not at 1 month of age, mice treated with doxycycline as pups show an 18% increase in nitrotyrosine in RPE/choroid samples, indicating increased oxidative stress
• increased oxidative stress in the RPE is confirmed by 8-OHdG staining and accumulation of 4-HNE-modified proteins and superoxide
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pigmentation
• at 6 weeks of age, neonatally doxycycline-induced mice show extensive oxidative damage to DNA in the RPE, as shown by 8-OHdG staining; most immunoreactivity is in the cytoplasm although some oxidative damage is seen in nuclei
• increased oxidative stress results in accumulation of 4-HNE-modified proteins and superoxide in the RPE
• at 4 months of age, autofluorescence in the RPE is increased by >20-fold, and basal infoldings of the RPE appear disordered
• by 9 months, overall RPE thickness is increased by ~30% relative to that at 1 month of age, with most thickening detected in the superior region (>40%)
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• by 6 months, doxycycline-induced mice show hypopigmented areas and white spots reflected thinning of the retina
|
• doxycycline-induced mice show slowly progressive retina atrophy during aging
• at 6 months or later, large regions of the RPE appear to be absent, with no intact ONL or photoreceptor layer
• by 9 months, disc membranes are more widely spaced, fragmented mitochondria accumulate along the basal surface of the RPE, membrane-filled vacuoles are seen in some areas, and apical microvilli are absent
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nervous system
• by 9 months, photoreceptor inner segments are severely shortened in some regions
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• by 9 months, photoreceptor outer segments are severely shortened in some regions
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• by 9 months, the length of rod outer segments is increased in many areas of the retina, with gaps between disc membranes
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cardiovascular system
• doxycycline-induced mice show abnormal retinal blood vessels starting at ~6 months of age
• fluorescein angiography revealed vascular leakage in regions of atrophy, with twisted major blood vessels, vascular beading, and increased branching and dilation of deeper blood vessels
• however, no signs of choroidal neovascularization are observed
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• at 9 months of age, one doxycycline-induced mouse showed subretinal hemorrhage between the photoreceptors and RPE
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