title: Mead acid supplementation does not rescue rats from cataract and retinal degeneration induced by N-methyl-N-nitrosourea.
abstract: Fatty acids and their derivatives play a role in the response to ocular disease. Our current study investigated the effects of dietary mead acid (MA, 5,8,11-eicosatrienoic acid) supplementation on N-methyl-N-nitrosourea (MNU)-induced cataract and retinal degeneration in Sprague-Dawley rats. Experiment 1 was designed to inhibit cataract formation, with the dams fed a 2.4% MA or basal (<0.01% MA) diet during lactational periods. On postnatal day 7, male pups received a single intraperitoneal (ip) injection of 50 mg/kg MNU or vehicle. Lens opacity and morphology were examined 7 and 14 days after the MNU injection. Experiment 2 was designed to inhibit retinal degeneration and was performed with female postweaning rats. In this experiment, dams were fed the 2.4% MA or basal diet during the lactational periods. Thereafter, the female pups were continuously fed the same diets during their postweaning periods. On postnatal day 21 (at weaning), pups received a single ip injection of 50 mg/kg MNU. Retinal morphology was examined 7 days after the MNU injection. In experiment 3, six-week-old female rats were fed the 2.4% MA or basal diet starting at one week before the MNU injection and were then continuously fed the same diets until sacrifice. Rats at 7 weeks of age were given a single ip injection of 40 mg/kg MNU, and the retina was then examined morphologically one week after the MNU injection. In experiment 1, mature cataract was found in all of the MNU-treated groups, with or without MA supplementation. In experiments 2 and 3, atrophy of both the peripheral and central outer retina occurred in all rats exposed to MNU, with or without MA supplementation, respectively. The severities of the cataracts and retinal atrophy in the rats were similar regardless of MA supplementation. Dietary mead acid, which is used as a substitute in essential fatty acid deficiency in the body, does not modify MNU-induced cataract and retinal degeneration in rat models.
authors.affiliation: Department of Pathology II, Kansai Medical University, 2-5-1 Shin-machi, Hirakata, Osaka 573-1010, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Emoto
authors.affiliation: Department of Pathology II, Kansai Medical University, 2-5-1 Shin-machi, Hirakata, Osaka 573-1010, Japan.
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Yoshizawa
authors.affiliation: Department of Public Health, Faculty of Medicine, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Hamazaki
authors.affiliation: Department of Pathology II, Kansai Medical University, 2-5-1 Shin-machi, Hirakata, Osaka 573-1010, Japan. ; Division of Pathology, Kansai Medical University Takii Hospital, 10-15 Fumizono, Moriguchi, Osaka 570-8507, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Kinoshita
authors.affiliation: Department of Pathology II, Kansai Medical University, 2-5-1 Shin-machi, Hirakata, Osaka 573-1010, Japan.
authors.forename: Michiko
authors.initials: M
authors.lastname: Yuki
authors.affiliation: Department of Pathology II, Kansai Medical University, 2-5-1 Shin-machi, Hirakata, Osaka 573-1010, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yuri
authors.affiliation: Institute for Health Care Science, Suntory Wellness Ltd., 1-1-1 Wakayamadai, Shimamoto, Osaka 618-8503, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kawashima
authors.affiliation: Department of Pathology II, Kansai Medical University, 2-5-1 Shin-machi, Hirakata, Osaka 573-1010, Japan.
authors.forename: Airo
authors.initials: A
authors.lastname: Tsubura
keywords: N-methyl-N-nitrosourea; arachidonic acid; cataract; mead acid; rats; retinal degeneration