The role of nitric oxide in the apoptosis of neurons in the retina of the human fetal eye

• Published in: Neuroscience and behavioral physiology 2007-02, Vol.37 (2), p.111-118
• Main Authors: Matveeva, N Yu, Kalinichenko, S G, Pushchin, I I, Motavkin, P A
• Format: Article
• Language: English
• Subjects: Abortion; Age Factors; Antibodies; Apoptosis; Apoptosis - physiology; Eye - cytology; Eye - embryology; Female; Fetus; Fetuses; Humans; Immunohistochemistry - methods; In Situ Nick-End Labeling - methods; Laboratories; Microscopy, Electron, Transmission; NADPH Dehydrogenase - metabolism; Neurons; Neurons - classification; Neurons - enzymology; Neurons - ultrastructure; Nitric oxide; Nitric Oxide - metabolism; Nitric Oxide Synthase Type II - metabolism; Physiology; Pregnancy; Retina; Retina - cytology; Retina - embryology; Retina - metabolism
• ISSN: 0097-0549; 1573-899X
• DOI: 10.1007/s11055-007-0157-6

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.