Aging related changes of retina and optic nerve of Uromastyx aegyptia and Falco tinnunculus.
Aging is a biological phenomenon that involves gradual degradation of the structure and function of the retina and optic nerve. To our knowledge, little is known about the aging-related ocular cell loss in avian (Falco tinnunculus) and reptilian species (Uromastyx aegyptia). A selected 90 animals of pup, middle, and old age U. aegyptia (reptilian) and F. tinnunculus (avian) were used. The retinae and optic nerves were investigated by light and transmission electron microscopy (TEM) and assessments of neurotransmitters, antioxidant enzymes (catalase, superoxide dismustase and glutathione s transferase), caspase-3 and -7, malonadialdhyde, and DNA fragmentation. Light and TEM observations of the senile specimens revealed apparent deterioration of retinal cell layers, especially the pigmented epithelium and photoreceptor outer segments. Their inclusions of melanin were replaced by lipofuscins. Also, vacuolar degeneration and demyelination of the optic nerve axons were detected. Concomitantly, there was a marked increase of oxidative stress involved reduction of neurotransmitters and antioxidant enzymes and an increase of lipid peroxidation, caspase-3 and -7, subG0/G1 apoptosis, and P53. We conclude that aging showed an inverse relationship with the neurotransmitters and antioxidant enzymes and a linear relationship of caspases, malondialdhyde, DNA apoptosis, and P53 markers of cell death. These markers reflected the retinal cytological alterations and lipofuscin accumulation within inner segments.
Department of Zoology, Faculty of Science, Mansoura University , Mansoura 002050, Egypt.
Hassan I H
HI
El-Sayyad
Soad A
SA
Khalifa
Asma S
AS
Al-Gebaly
Ahmed A
AA
El-Mansy
D000367:Age Factors; D000375:Aging; D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000502:physiology; D002374:Catalase / Q000378:metabolism; D046093:Falconiformes / Q000033:anatomy & histology* / Q000254:growth & development; D005982:Glutathione Transferase / Q000378:metabolism; D008315:Malondialdehyde / Q000378:metabolism; D046529:Microscopy, Electron, Transmission; D018377:Neurotransmitter Agents / Q000378:metabolism; D009900:Optic Nerve / Q000033:anatomy & histology* / Q000254:growth & development* / Q000378:metabolism / Q000648:ultrastructure; D012104:Reptiles / Q000033:anatomy & histology* / Q000254:growth & development; D012160:Retina / Q000033:anatomy & histology / Q000254:growth & development* / Q000378:metabolism / Q000648:ultrastructure; D013482:Superoxide Dismutase / Q000378:metabolism; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
D018377:Neurotransmitter Agents; D017392:Thiobarbituric Acid Reactive Substances; D016159:Tumor Suppressor Protein p53; D008315:Malondialdehyde; D002374:Catalase; D013482:Superoxide Dismutase; D005982:Glutathione Transferase