A dietary combination of omega-3 and omega-6 polyunsaturated fatty acids is more efficient than single supplementations in the prevention of retinal damage induced by elevation of intraocular pressure in rats.
BACKGROUND
To evaluate the effect of a dietary combination of omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) compared to single PUFA supplementations on the outcome of a substantial elevation of intraocular pressure (IOP) in rats.


METHODS
Sprague Dawley rats were fed for 6 months with either a control diet, a diet enriched with omega-3 PUFAs (eicosapentaenoic acid, EPA, and docosahexaenoic acid, DHA), a diet enriched with omega-6 PUFAs (gamma-linolenic acid, GLA) or a diet enriched with both omega-3 and omega-6 PUFAs (EPA + DHA and GLA). After 3 months of feeding, elevation of IOP was induced by photocoagulation of the episcleral veins, limbus and trabecular meshwork using a 532-nm laser. IOP and scotopic electroretinograms (ERGs) were monitored after the induction of IOP elevation until the end of the nutritional supplementation. Retinal morphometry and GFAP immunohistochemistry were performed 3 months after laser photocoagulation. Retinal ganglion cells (RGCs) were quantified using retrograde labelling.


RESULTS
A significant rise in IOP was observed in the laser-treated eyes. PUFA supplementation did not influence the time course of IOP in the laser-treated eyes. Three months after laser photocoagulation, the activation of glial cells observed in the laser-treated eyes was significantly lower in animals fed with the EPA + DHA + GLA diet when compared to those fed the control diet, while single supplementations with either EPA + DHA or GLA were not effective. The same protective effect of the EPA + DHA + GLA combination was observed on retinal structures in the laser-treated eyes. However, PUFA supplementation did not influence either ERG b-wave amplitude or the RGC loss in the laser-treated eyes.


CONCLUSIONS
This study demonstrates that a 6-month supplementation with a combination of omega-3 and omega-6 PUFAs is more effective than single supplementations, since the EPA + DHA + GLA dietary combination prevented retinal cell structure and decreased glial cell activation induced by the elevation of IOP in rats.
INRA, UMR1129 FLAVIC, Eye and Nutrition Research Group, Dijon F-21000, France.
Coralie
C
Schnebelen
Bruno
B
Pasquis
Manuel
M
Salinas-Navarro
Corinne
C
Joffre
Catherine P
CP
Creuzot-Garcher
Manuel
M
Vidal-Sanz
Alain M
AM
Bron
Lionel
L
Bretillon
Niyazi
N
Acar
D000818:Animals; D002452:Cell Count; D002470:Cell Survival; D019587:Dietary Supplements; D004195:Disease Models, Animal; D004596:Electroretinography; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage*; D043371:Fatty Acids, Omega-6 / Q000008:administration & dosage*; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D007429:Intraocular Pressure; D008297:Male; D009457:Neuroglia / Q000502:physiology; D009798:Ocular Hypertension / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D009901:Optic Nerve Diseases / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012164:Retinal Diseases / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D012165:Retinal Ganglion Cells / Q000502:physiology*
D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D005904:Glial Fibrillary Acidic Protein