Limits...
High levels of retinal docosahexaenoic acid do not protect photoreceptor degeneration in VPP transgenic mice.

Li F, Marchette LD, Brush RS, Elliott MH, Davis KR, Anderson AG, Anderson RE - Mol. Vis. (2010)

Bottom Line: Offspring were genotyped and four groups identified: Fat1(+)/VPP(+), Fat1(-)/VPP(+), Fat1(+)/VPP(-), and Fat1(-)/VPP(-).Dams were maintained on the SFO diet during the nursing period and offspring were kept on the SFO diet after weaning.There were no significant differences in outer nuclear layer thickness or ERG amplitudes between Fat1(+)/VPP(+) and Fat1(-)/VPP(+), or between Fat1(+)/VPP(-)and Fat1(-)/VPP(-) mice at any of the three ages.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.

ABSTRACT

Purpose: To determine whether docosahexaenoic acid can protect against hereditary retinal degenerations in transgenic mice expressing the V20G, P23H, and P27L (VPP) rhodopsin mutations.

Methods: Female transgenic mice expressing the VPP rhodopsin mutation, known to cause a retinal degeneration, were bred to male transgenic mice expressing the fat-1 gene, which can convert n6 to n3 polyunsaturated fatty acids (PUFA). Several weeks before breeding, the female mice were fed a standard diet containing 10% safflower oil (SFO), which is high in n6 and low in n3 PUFA (n6/n3=273). Offspring were genotyped and four groups identified: Fat1(+)/VPP(+), Fat1(-)/VPP(+), Fat1(+)/VPP(-), and Fat1(-)/VPP(-). Dams were maintained on the SFO diet during the nursing period and offspring were kept on the SFO diet after weaning. At 4, 16, and 28 weeks of age, retinal function was evaluated by electroretinography (ERG), photoreceptor cell loss was quantified by measuring outer nuclear layer thickness, and rhodopsin levels were determined. Fatty acid profiles were analyzed in whole retina, plasma, and liver at 4 and 28 weeks of age.

Results: Expression of fat-1 in the absence of dietary n3 PUFA led to the generation of two groups of mice with distinctly different levels of n3 and n6 PUFA in the three tissues that were analyzed. Already at four weeks of age, the retinas of fat-1 positive animals had higher levels of n3 PUFA than their wild-type counterparts (23%-29% versus 6.4%-6.5%). In addition, by four weeks of age, there was a significant loss of rod photoreceptor cells in the VPP mice. Progression of retinal degeneration occurred with increasing age in VPP positive mice, with photoreceptor cell death occurring in both inferior and superior regions. Amplitudes of the a- and b-waves of the ERG were significantly reduced with age, with VPP positive mice showing the greatest change. Rhodopsin content was lower in the VPP transgenic mice. There were no significant differences in outer nuclear layer thickness or ERG amplitudes between Fat1(+)/VPP(+) and Fat1(-)/VPP(+), or between Fat1(+)/VPP(-)and Fat1(-)/VPP(-) mice at any of the three ages.

Conclusions: High levels of retinal docosahexaenoic acid do not protect mice expressing the VPP rhodopsin mutation from retinal degeneration.

Show MeSH

Related in: MedlinePlus

Plasma fatty acid composition. A: The relative mole percentage of n3 and n6 polyunsaturated fatty acids from total phospholipid extracts of plasma of Fat1+/VPP+, Fat1–/VPP+, Fat1+/VPP–, and Fat1–/VPP– mice are shown at 4 weeks of age. B: Relative mole percentages at 28 weeks of age are shown. (n=3–7) *p<0.05 fat-1 positive versus fat-1 negative. **p<0.01 fat-1 positive versus fat-1 negative. ***p<0.001 fat-1 positive versus fat-1 negative. F indicates fat-1 and V indicates VPP.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2927381&req=5

f1: Plasma fatty acid composition. A: The relative mole percentage of n3 and n6 polyunsaturated fatty acids from total phospholipid extracts of plasma of Fat1+/VPP+, Fat1–/VPP+, Fat1+/VPP–, and Fat1–/VPP– mice are shown at 4 weeks of age. B: Relative mole percentages at 28 weeks of age are shown. (n=3–7) *p<0.05 fat-1 positive versus fat-1 negative. **p<0.01 fat-1 positive versus fat-1 negative. ***p<0.001 fat-1 positive versus fat-1 negative. F indicates fat-1 and V indicates VPP.

Mentions: We analyzed the fatty acid composition of retina total lipids, plasma phospholipids, and liver phospholipids from the four groups of mice at 4 and 28 weeks of age (see Table 1) for levels of polyunsaturated fatty acids. A complete fatty acid analysis of similar animals is given in the Supplemental Material [44]. Fatty acid composition of plasma (Figure 1; n=3–7) and liver (Figure 2; n=4–7) show significantly higher levels of n3 (p<0.01–0.001) and lower levels of n6 PUFA (p<0.05–0.001) in the fat-1 mice at 4 weeks (Figure 1A, 2A) and 28 weeks (Figure 1B, Figure 2B) of age, compared to their fat-1 negative littermates. Consequently, the n6/n3 ratios for fat-1 mice were significantly lower than their fat-1 negative littermates (Table 1). There were only minor differences in the levels of 18:2n6, the sole source of PUFA in the diet. The expression of the transgene had no effect on saturated and monoenoic fatty acid levels in the plasma or liver.


High levels of retinal docosahexaenoic acid do not protect photoreceptor degeneration in VPP transgenic mice.

Li F, Marchette LD, Brush RS, Elliott MH, Davis KR, Anderson AG, Anderson RE - Mol. Vis. (2010)

Plasma fatty acid composition. A: The relative mole percentage of n3 and n6 polyunsaturated fatty acids from total phospholipid extracts of plasma of Fat1+/VPP+, Fat1–/VPP+, Fat1+/VPP–, and Fat1–/VPP– mice are shown at 4 weeks of age. B: Relative mole percentages at 28 weeks of age are shown. (n=3–7) *p<0.05 fat-1 positive versus fat-1 negative. **p<0.01 fat-1 positive versus fat-1 negative. ***p<0.001 fat-1 positive versus fat-1 negative. F indicates fat-1 and V indicates VPP.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2927381&req=5

f1: Plasma fatty acid composition. A: The relative mole percentage of n3 and n6 polyunsaturated fatty acids from total phospholipid extracts of plasma of Fat1+/VPP+, Fat1–/VPP+, Fat1+/VPP–, and Fat1–/VPP– mice are shown at 4 weeks of age. B: Relative mole percentages at 28 weeks of age are shown. (n=3–7) *p<0.05 fat-1 positive versus fat-1 negative. **p<0.01 fat-1 positive versus fat-1 negative. ***p<0.001 fat-1 positive versus fat-1 negative. F indicates fat-1 and V indicates VPP.
Mentions: We analyzed the fatty acid composition of retina total lipids, plasma phospholipids, and liver phospholipids from the four groups of mice at 4 and 28 weeks of age (see Table 1) for levels of polyunsaturated fatty acids. A complete fatty acid analysis of similar animals is given in the Supplemental Material [44]. Fatty acid composition of plasma (Figure 1; n=3–7) and liver (Figure 2; n=4–7) show significantly higher levels of n3 (p<0.01–0.001) and lower levels of n6 PUFA (p<0.05–0.001) in the fat-1 mice at 4 weeks (Figure 1A, 2A) and 28 weeks (Figure 1B, Figure 2B) of age, compared to their fat-1 negative littermates. Consequently, the n6/n3 ratios for fat-1 mice were significantly lower than their fat-1 negative littermates (Table 1). There were only minor differences in the levels of 18:2n6, the sole source of PUFA in the diet. The expression of the transgene had no effect on saturated and monoenoic fatty acid levels in the plasma or liver.

Bottom Line: Offspring were genotyped and four groups identified: Fat1(+)/VPP(+), Fat1(-)/VPP(+), Fat1(+)/VPP(-), and Fat1(-)/VPP(-).Dams were maintained on the SFO diet during the nursing period and offspring were kept on the SFO diet after weaning.There were no significant differences in outer nuclear layer thickness or ERG amplitudes between Fat1(+)/VPP(+) and Fat1(-)/VPP(+), or between Fat1(+)/VPP(-)and Fat1(-)/VPP(-) mice at any of the three ages.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.

ABSTRACT

Purpose: To determine whether docosahexaenoic acid can protect against hereditary retinal degenerations in transgenic mice expressing the V20G, P23H, and P27L (VPP) rhodopsin mutations.

Methods: Female transgenic mice expressing the VPP rhodopsin mutation, known to cause a retinal degeneration, were bred to male transgenic mice expressing the fat-1 gene, which can convert n6 to n3 polyunsaturated fatty acids (PUFA). Several weeks before breeding, the female mice were fed a standard diet containing 10% safflower oil (SFO), which is high in n6 and low in n3 PUFA (n6/n3=273). Offspring were genotyped and four groups identified: Fat1(+)/VPP(+), Fat1(-)/VPP(+), Fat1(+)/VPP(-), and Fat1(-)/VPP(-). Dams were maintained on the SFO diet during the nursing period and offspring were kept on the SFO diet after weaning. At 4, 16, and 28 weeks of age, retinal function was evaluated by electroretinography (ERG), photoreceptor cell loss was quantified by measuring outer nuclear layer thickness, and rhodopsin levels were determined. Fatty acid profiles were analyzed in whole retina, plasma, and liver at 4 and 28 weeks of age.

Results: Expression of fat-1 in the absence of dietary n3 PUFA led to the generation of two groups of mice with distinctly different levels of n3 and n6 PUFA in the three tissues that were analyzed. Already at four weeks of age, the retinas of fat-1 positive animals had higher levels of n3 PUFA than their wild-type counterparts (23%-29% versus 6.4%-6.5%). In addition, by four weeks of age, there was a significant loss of rod photoreceptor cells in the VPP mice. Progression of retinal degeneration occurred with increasing age in VPP positive mice, with photoreceptor cell death occurring in both inferior and superior regions. Amplitudes of the a- and b-waves of the ERG were significantly reduced with age, with VPP positive mice showing the greatest change. Rhodopsin content was lower in the VPP transgenic mice. There were no significant differences in outer nuclear layer thickness or ERG amplitudes between Fat1(+)/VPP(+) and Fat1(-)/VPP(+), or between Fat1(+)/VPP(-)and Fat1(-)/VPP(-) mice at any of the three ages.

Conclusions: High levels of retinal docosahexaenoic acid do not protect mice expressing the VPP rhodopsin mutation from retinal degeneration.

Show MeSH
Related in: MedlinePlus