title: No consequences of dietary n-3 polyunsaturated fatty acid deficiency on the severity of scopolamine-induced dry eye.
abstract: OBJECTIVE
  Epidemiological studies suggest that dietary n-3 polyunsaturated fatty acids (PUFAs) may protect against dry eye. This study aimed to evaluate whether a dietary deficiency in n-3 PUFAs may increase the severity of the pathology in a scopolamine-induced model of dry eye in the rat.
  
  
  METHODS
  Lewis rats of three consecutive generations were bred under a balanced diet or a diet deprived of n-3 PUFAs. Dry eye was experimentally induced by continuous scopolamine delivery in female animals from the third generation of both groups. After 10 days of treatment, the clinical signs of ocular dryness were evaluated in vivo using fluorescein staining. MHC II and the rat mucin rMuc5AC were immunostained on ocular sphere cryosections. The transcript levels of the pro-inflammatory cytokines interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α and interferon (IFN)-γ were quantified in the exorbital lacrimal glands (LG) and in the conjunctiva using reverse transcription followed by polymerase chain reaction. Lipids were extracted from the exorbital LG for fatty acid analysis of the phospholipids using gas chromatography.
  
  
  RESULTS
  When compared to control animals, the scopolamine treatment induced an increase in the cornea fluorescein staining score (from 0.5 ± 0.0 to 2.5 ± 1.0 arbitrary units (AU) for the balanced diet and from 1.2 ± 0.8 to 2.6 ± 0.5 AU for the n-3 PUFA-deficient diet); a decrease in rMuc5AC immunostaining in the conjunctival epithelium (-34% for the balanced diet and -23% for the n-3 PUFA-deficient diet); an increase in the LG transcript levels of TNF-α for the balanced diet and of TNF-α and IFN-γ for the deficient diet; an increase in the conjunctival transcript levels of IL-1β and IL-6 for the deficient diet; an increase in arachidonic acid (AA) and in the ∆5-desaturase index (ratio of AA to dihomo-gamma-linolenic acid) in the exorbital LG for both diets. When compared to the balanced diet, the n-3 PUFA-deficient diet induced an increase in the LG transcript levels of IL-6 for the control animals and of TNF-α for the control and dry eye animals as well as an increase in the conjunctival transcript levels of IL-6 for the dry eye animals. There was no significant diet difference in fluorescein staining, rMuc5AC, and MHC II immunostaining scores.
  
  
  CONCLUSIONS
  Our data suggest that an n-3 PUFA deficiency does not increase the severity of dry eye in a rat model of dry eye.
authors.affiliation: Eye and Nutrition Research Group, UMR CSGA INRA - CNRS, Université de Bourgogne, Dijon, France.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Viau
authors.forename: Bruno
authors.initials: B
authors.lastname: Pasquis
authors.forename: Marie-Annick
authors.initials: MA
authors.lastname: Maire
authors.forename: Cynthia
authors.initials: C
authors.lastname: Fourgeux
authors.forename: Stéphane
authors.initials: S
authors.lastname: Grégoire
authors.forename: Niyazi
authors.initials: N
authors.lastname: Acar
authors.forename: Lionel
authors.initials: L
authors.lastname: Bretillon
authors.forename: Catherine P
authors.initials: CP
authors.lastname: Creuzot-Garcher
authors.forename: Corinne
authors.initials: C
authors.lastname: Joffre
mesh_terms: D000818:Animals; D002849:Chromatography, Gas; D003228:Conjunctiva / Q000378:metabolism* / Q000473:pathology; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D004042:Dietary Fats, Unsaturated; D004195:Disease Models, Animal; D015352:Dry Eye Syndromes / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology; D015525:Fatty Acids, Omega-3 / Q000378:metabolism*; D005260:Female; D000949:Histocompatibility Antigens Class II / Q000235:genetics / Q000378:metabolism; D007765:Lacrimal Apparatus / Q000378:metabolism* / Q000473:pathology; D008055:Lipids / Q000172:deficiency; D055271:Mucin 5AC / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011917:Rats, Inbred Lew; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012601:Scopolamine; D012720:Severity of Illness Index
chemical_list: D016207:Cytokines; D004042:Dietary Fats, Unsaturated; D015525:Fatty Acids, Omega-3; D000949:Histocompatibility Antigens Class II; D008055:Lipids; C524680:Muc5ac protein, rat; D055271:Mucin 5AC; D012601:Scopolamine