The role of nitric oxide in the apoptosis of neurons in the retina of the human fetal eye.
The locations of NADPH-diaphorase (NADPH-d), inducible NO synthase (iNOS), and TUNEL-immunoreactive neurons in the retina of human fetuses collected during the first to third trimesters of pregnancy were studied. High levels of NADPH-d activity were seen in the inner segments of light-sensitive cells, amacrine cells, and ganglion cells. The population of NADPH-d-positive amacrine cells included three types of neuron. Type 1 neurons were large and had sparse dendritic fields occupying the inner nuclear and outer retinal layers. Small type 2 neurons were located in the inner retinal layer. Ectopic amacrine cells, type 3, were located in the outer part of the ganglion layer. A high density of NADPH-d-positive neurons was seen in the central part of the retina, surrounding the central fovea and optic disk area. NADPH-d activity increased progressively during ontogenesis and correlated with the appearance of immunoreactive iNOS in neurons. iNOS labeled a subpopulation of amacrine and ganglion cells, which appeared at 20-21 weeks of development and reached a peak of immunoreactivity by the end of the third trimester. TUNEL-immunopositive neuron nuclei with signs of apoptotic destruction were seen at 30-31 weeks of pregnancy. The greatest apoptotic index was seen in the ganglion and amacrine cell populations. These data identify NO as a factor mediating apoptosis of neurons during the critical period of differentiation of interneuronal connections in the human retina.
Matveeva
N Yu
NY
Faculty of Histology, Vladivostok State Medical University, Vladivostok, Russia.
Kalinichenko
S G
SG
Pushchin
I I
II
Motavkin
P A
PA
D000367:Age Factors; D017209:Apoptosis / Q000502:physiology*; D005123:Eye / Q000166:cytology / Q000196:embryology; D005260:Female; D005333:Fetus; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D020287:In Situ Nick-End Labeling / Q000379:methods; D046529:Microscopy, Electron, Transmission; D009252:NADPH Dehydrogenase / Q000378:metabolism; D009474:Neurons / Q000145:classification / Q000201:enzymology* / Q000648:ultrastructure; D009569:Nitric Oxide / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D011247:Pregnancy; D012160:Retina / Q000166:cytology / Q000196:embryology / Q000378:metabolism
D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D009252:NADPH Dehydrogenase