OBJECTIVETo understand the function of Sonic hedgehog in chiasm development in mouse embryos of embryonic day 13 (E13) to E15.

METHODSBrain slices of E13-E15 mouse embryos containing the optic pathway from the eyes to the optic tract were prepared and cultured in DMEM/F12 in the presence of 10% fetal bovine serum at 37 degrees in a rolling incubator for 5 h. The antibody to Shh was added into the culture medium of the slices in the treatment group, while no additional chemical or only normal mouse IgG was added in the control groups. After culture, the brain slices were fixed and a DiI granule was inserted into the optic disc in one eye. Seven days later, the tissue overlying the chiasm was removed to expose the DiI-labeled chiasm for observation under confocal microscope, and the images were analyzed by METAMORPH software.

RESULTSShh antibody treatment produced a reduction of crossing of the earliest retinal axons at the midline of E13 chiasm, and the uncrossed axons were also influenced by Shh antibody at E15.

CONCLUSIONShh executes a transient but important function in axon decussation in the early stage of mouse optic chiasm development and signals axon turning in the later stage.

Animals ; Antibodies ; immunology ; metabolism ; Hedgehog Proteins ; immunology ; metabolism ; Mice ; Neural Pathways ; embryology ; metabolism ; Optic Chiasm ; embryology ; metabolism ; Retina ; embryology ; metabolism ; Signal Transduction ; Tissue Culture Techniques

In the present study the specific and nonspecific cholinesterase activities of the rabbit's retinae in the fetus, the neonatal, the light-isolated, and the reopened group, which consisted of 65 healthy young rabbits, weighing about 300 to 500 gm, 33 rabbit's fetuses, and neonatal rabbits, were histochemically ovserved by means of the cholinesterase method recommended by Gerebtzoff (1953) and the embedding and sectioning method pesented by Koelle and Friedenwald (1950). Cholinesterase activity of the retinae in the 15 days fetuses was not present but began to develop in the 20 days fetuses. In the 1 week group after suturing the eyelids, the most remarkable activity of specific and nonspecific cholinesterase was observed in the posterior polar area. The nearer to the peripheral area of the retina the weaker the enzymetic activities became. In the 2 weeks group after suturing eyelids, the enzymatic activity was reduced. In the 4, and 8weeks groups after suturing the eyelides, the enzymatic activities were remarkably reduced. In the l4 days after reopening eyelide, which group has previously been kept under the condition of light isolation for 4 weeks, enzymatic activities were fairly recovered and compared with the normal control group. Consequently it is histochemically deduced that the gradual change of specific cholinesterase activities in the rabbit's retinae was closely related to the visual function.
Animals ; Animals, Newborn/enzymology ; Cholinesterases/*metabolism ; Histocytochemistry ; *Rabbits ; Retina/embryology/*enzymology

OBJECTIVETo examine the change of Smoothened (Smo) expression in the retinofugal pathway and in the growth cones during the period of embryonic day 13 (E13) to E15.

METHODSSmo expression in the chiasm and growth cones was observed by fluorescent immunostaining and retinal explant culture.

RESULTSOn E13 and E14, Smo was expressed moderately in the retina and optic disc, and in the corner of the retina, Smo expression was especially dense. On E13, Smo expression was detected in the optic nerves and ventral diencephalon, but only in the superficial region of the optic tract on E14. Smo was also detected in the stem and filopodia of the growth cones in the retinal explant culture during this period.

CONCLUSIONSmo expression changes in different developmental phases, suggesting that Smo might play a role in signal optic axon growth during the development of the retinofugal pathway.

Animals ; Fluorescent Antibody Technique ; Mice ; Mice, Inbred C57BL ; Optic Chiasm ; cytology ; embryology ; metabolism ; Optic Nerve ; cytology ; embryology ; metabolism ; Receptors, G-Protein-Coupled ; biosynthesis ; Retina ; cytology ; embryology ; metabolism ; Smoothened Receptor ; Visual Pathways ; cytology ; embryology ; metabolism

The purpose of this study was to measure the level of expression of the inducible heat shock protein70 (Hsp70), the constitutive heat shock protein70 (Hsc70) in the outer nuclear layer and the photoreceptors in the human fetal retina. Fetal eyeballs were selected from fetal autopsy specimens of 12 and 17 to 40 week old fetuses, with no history of congenital anomalies. The retinas had differentiated from neuroblastic cells, into matured sensory retinas, from a gestational age (GA) from 12 to 36 weeks. The Hsp70 and Hsc70 were prominently expressed in the nuclear layers. The Hsc70 was expressed at all GAs and the Hsp70 was expressed from 20 to 33 weeks GA. This period is in accordance with the maturation of the sensory retina. The expression of heat shock protein may be regulated by the development of the fetus, and play an important role in the ocular development.
Embryo and Fetal Development ; Fetus/metabolism ; Heat-Shock Proteins 70/*metabolism ; Human ; Immunohistochemistry ; Retina/*embryology ; Support, Non-U.S. Gov't

BACKGROUNDRetina is important in converting light into neural signals, but little is known about the regulatory genes essential for the retinal morphological formation, development and functional differentiation. This study aimed to investigate the mRNA expression patterns and cellular or subcellular distribution of 33 differentially expressed genes in the retina belonging to the early and middle-late embryogenesis stages as well as the early adult stage during human development.

METHODSIn situ hybridization and real-time fluorescent quantitative reverse transcription polymerase chain reaction (FQ-RT-PCR) were used to assay 33 differentially expressed genes which were screened out using microarray analysis and were not present in the retinal cDNA or the Expressed Sequence Tags (EST) database of the National Eye Institute (NEI) Genebank.

RESULTSNine of the 33 genes belonged to EST or the unknown cDNA fragments, and the remaining belonged to the novel genes in the retina. During the human retinal development 17 genes were down-regulated, 6 were up-regulated and the remaining 10 were relatively unchanged. Most of the genes expressed in all layers of the retina at the gestation stage, and in the fully developed retina some genes examined did show higher expression level in certain specific cells and structures such as retinal ganglion cells or the outer segment of photoreceptor cells.

CONCLUSIONThe gene expression profile during retinal development possesses temporal and spatial distribution features, which can provide experimental evidence for further research of the functions of those genes.

Expressed Sequence Tags ; Fetus ; metabolism ; Gene Expression Profiling ; Humans ; In Situ Hybridization ; RNA, Messenger ; analysis ; Retina ; embryology ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction