title: Analysis of fine structure and biochemical changes of retina during aging of Wistar albino rats.
abstract: BACKGROUND
  Aging is a biological phenomenon that involves an increase of oxidative stress associated with gradual degradation of the structure and function of the retina. Gender differences and subsequent deterioration of retinal cell layers is an interesting topic, especially because there is no published work concerning it.
  
  
  METHODS
  One hundred and twenty male and female Wistar albino rats ages 1, 6, 18, 30 and 42 months (n = 20 equal for male and female) were used. At the time interval, retinae were investigated by light and transmission electron microscopy, assessments of neurotransmitters, anti-oxidant enzymes (catalase, superoxide dismustase and glutathione S transferase), caspase-3 and -7, malonadialdhyde, and DNA fragmentation.
  
  
  RESULTS
  Light and transmission electron microscopy observations of the older specimens (30 and 42 months) revealed apparent deterioration of retinal cell layers, especially ganglion and nerve fibres, nuclear, pigmented epithelium and stacked membranes of the photoreceptor's outer segments. Males were highly susceptible to aging processes. Retinal DNA fragmentation was remarked parallel with increase of apoptic markers caspase 3 and 7. Concomitantly, there was a marked reduction of neurotransmitters and anti-oxidant enzymes, and an increase of lipid peroxidation.
  
  
  CONCLUSIONS
  Aging contributed to an increase of oxidative stress resulting from damage of mitochondria in retinal cells, a decrease of the anti-oxidant enzyme system and an increase of markers of retinal cell death.
authors.affiliation: Department of Zoology, Faculty of Science, Mansoura University, Mansoura, Egypt.
authors.forename: Hassan I H
authors.initials: HI
authors.lastname: El-Sayyad
authors.forename: Soad A
authors.initials: SA
authors.lastname: Khalifa
authors.forename: Fawkia I
authors.initials: FI
authors.lastname: El-Sayyad
authors.forename: Shaker A
authors.initials: SA
authors.lastname: Mousa
authors.forename: Ezaldin A M
authors.initials: EA
authors.lastname: Mohammed
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D017209:Apoptosis / Q000502:physiology; D053148:Caspase 3 / Q000378:metabolism; D053179:Caspase 7 / Q000378:metabolism; D002452:Cell Count; D020552:Comet Assay; D004249:DNA Damage / Q000502:physiology; D005136:Eye Proteins / Q000378:metabolism*; D005260:Female; D015227:Lipid Peroxidation; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D046529:Microscopy, Electron, Transmission; D018377:Neurotransmitter Agents / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology; D010088:Oxidoreductases / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012160:Retina / Q000378:metabolism* / Q000648:ultrastructure*; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism
chemical_list: D005136:Eye Proteins; D018377:Neurotransmitter Agents; D017392:Thiobarbituric Acid Reactive Substances; D008315:Malondialdehyde; D010088:Oxidoreductases; C505410:Casp3 protein, rat; D053148:Caspase 3; D053179:Caspase 7
keywords: aging; light and transmission electron microscopy; molecular analysis; retina