Neurodegenerative influence of oxidative stress in the retina of a murine model of diabetes - PubMed (original) (raw)

Neurodegenerative influence of oxidative stress in the retina of a murine model of diabetes

M Sasaki et al. Diabetologia. 2010 May.

Abstract

Aims/hypothesis: Diabetic retinopathy is a progressive neurodegenerative disease, but the underlying mechanism is still obscure. Here, we focused on oxidative stress in the retina, and analysed its influence on retinal neurodegeneration, using an antioxidant, lutein.

Methods: C57BL/6 mice with streptozotocin-induced diabetes were constantly fed either a lutein-supplemented diet or a control diet from the onset of diabetes, and their metabolic data were recorded. In 1-month-diabetic mice, reactive oxygen species (ROS) in the retina were measured using dihydroethidium and visual function was evaluated by electroretinograms. Levels of activated extracellular signal-regulated kinase (ERK), synaptophysin and brain-derived neurotrophic factor (BDNF) were also measured by immunoblotting in the retina of 1-month-diabetic mice. In the retinal sections of 4-month-diabetic mice, histological changes, cleaved caspase-3 and TUNEL staining were analysed.

Results: Lutein did not affect the metabolic status of the diabetic mice, but it prevented ROS generation in the retina and the visual impairment induced by diabetes. ERK activation, the subsequent synaptophysin reduction, and the BDNF depletion in the diabetic retina were all prevented by lutein. Later, in 4-month-diabetic mice, a decrease in the thickness of the inner plexiform and nuclear layers, and ganglion cell number, together with increase in cleaved caspase-3- and TUNEL-positive cells, were avoided in the retina of lutein-fed mice.

Conclusions/interpretation: The results indicated that local oxidative stress that has a neurodegenerative influence in the diabetic retina is prevented by constant intake of a lutein-supplemented diet. The antioxidant, lutein may be a potential therapeutic approach to protect visual function in diabetes.

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Figures

Fig. 1

Fig. 1

Diabetes-induced oxidative stress in the retina was reduced by lutein. a DHE staining in the retinal section. Original magnification ×200; scale bar, 30 μm. b Fluorescence intensity in the INL relative to that of non-diabetic mice, measured by the Image J program. Note that ROS increased throughout the retina of mice diabetic for 1 month; however, this change was prevented by constant intake of lutein from the onset of diabetes. Non-diabetic mice, _n_=4; diabetic mice fed control diet, _n_=4; diabetic mice fed lutein diet, _n_=5. Values are means±SD. *p < 0.05, **p < 0.01

Fig. 2

Fig. 2

Diabetes-induced visual dysfunction was suppressed by lutein. Representative wave responses from an individual mouse in each group to one flash (a). Constant lutein intake from the onset of diabetes significantly inhibited the reduction of OP3 and total OPs (ΣOPs; summation of OP2, 3, and 4) amplitude in 1-month-diabetic mice (b). Black columns, non-diabetic mice, _n_=5; white columns, diabetic mice fed control diet, _n_=6; grey columns, diabetic mice fed lutein diet, _n_=6. Values are means±SD. *p < 0.05

Fig. 3

Fig. 3

Diabetes-induced biochemical changes in the retina are prevented by lutein as shown by immunoblot analysis. a, d Diabetes-induced ERK activation detected by ERK phosphorylation (pERK) in the retina of 1-month-diabetic mice was prevented by constant intake of lutein. Non-diabetic mice, _n_=8; diabetic mice fed control diet, _n_=8; diabetic mice fed lutein diet, _n_=7. b, e A decrease in synaptophysin in the retina of 1-month-diabetic mice was prevented by constant intake of lutein. Non-diabetic mice, _n_=6; diabetic mice fed control diet, _n_=6; diabetic mice fed lutein diet, _n_=6. c, f The level of BDNF was also reduced in the retina of 1-month-diabetic mice, and was significantly rescued by constant intake of lutein. Non-diabetic, mice _n_=6; diabetic mice fed control diet, _n_=6; diabetic mice fed lutein diet, _n_=6. Bar graph values are relative to those of the non-diabetic controls. Values are means±SD. *p < 0.05, **p < 0.01

Fig. 4

Fig. 4

Diabetes-induced histological changes were suppressed by lutein. Thickness of each retinal layer was measured in paraffin sections after haematoxylin and eosin staining. Original magnification ×400. a Relative thicknesses of IPL and INL, normalised to ONL measured at the same point, respectively, were reduced in the retina of 4-month-diabetic mice, but remained normal in the diabetic mice fed the lutein diet all the time from diabetes onset. b The neuronal cell number in the GCL in one cross-section of the mice diabetic for 4 months was decreased; however, this change was significantly suppressed by lutein. Black columns, non-diabetic mice, _n_=6; white columns, diabetic mice fed control diet, _n_=5; grey columns, diabetic mice fed lutein diet, _n_=5. Values are means±SD. *p < 0.05, **p < 0.01

Fig. 5

Fig. 5

Diabetes-induced apoptosis was inhibited by lutein. a Caspase-3 activation detected by immunohistochemistry of cleaved caspase-3. Caspase-3 activation was obvious in GCL and weak in INL cells of 4-month-diabetic retinas (arrowheads, cleaved caspase-3-positive cells); however, the activation was suppressed by constant intake of lutein. b TUNEL staining in the GCL of 4-month-diabetic retinas (arrowheads) was also suppressed by lutein treatment. Cleaved caspase-3-positive cells (c) and the TUNEL-positive cells (d) in GCL were counted. a, c Non-diabetic mice, _n_=4; diabetic mice fed control diet, _n_=4; diabetic mice fed lutein diet, _n_=4. b, d Non-diabetic mice, _n_=5; diabetic mice fed control diet, _n_=6; diabetic mice fed lutein diet, _n_=6. Value are means±SD. *p < 0.05, **p < 0.01. a Original magnification ×200, scale bar, 30 μm. b Original magnification ×400; scale bar, 40 μm

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References

    1. Barber AJ. A new view of diabetic retinopathy: a neurodegenerative disease of the eye. Prog Neuropsychopharmacol Biol Psychiatry. 2003;27:283–290. doi: 10.1016/S0278-5846(03)00023-X. - DOI - PubMed
    1. Dandona P, Thusu K, Cook S, et al. Oxidative damage to DNA in diabetes mellitus. Lancet. 1996;347:444–445. doi: 10.1016/S0140-6736(96)90013-6. - DOI - PubMed
    1. Lee HB, Yu MR, Yang Y, Jiang Z, Ha H. Reactive oxygen species-regulated signaling pathways in diabetic nephropathy. J Am Soc Nephrol. 2003;14:S241–S245. doi: 10.1097/01.ASN.0000077410.66390.0F. - DOI - PubMed
    1. Zheng L, Du Y, Miller C, et al. Critical role of inducible nitric oxide synthase in degeneration of retinal capillaries in mice with streptozotocin-induced diabetes. Diabetologia. 2007;50:1987–1996. doi: 10.1007/s00125-007-0734-9. - DOI - PubMed
    1. Rivero A, Mora C, Muros M, Garcia J, Herrera H, Navarro-Gonzalez JF. Pathogenic perspectives for the role of inflammation in diabetic nephropathy. Clin Sci (Lond) 2009;116:479–492. doi: 10.1042/CS20080394. - DOI - PubMed

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