Objective To observe the characteristics of morphological development of premature retina at 33-46 weeks of gestational corrected age (GCA). Methods A total of 268 premature infants were divided into 7 groups according to the GCA (33-34，35-36，37-38，39-40，41-42，43-44 and 45-46 weeks). The ocular fundus of those infants were recorded and analyzed by an indirect ophthalmoscopelinked imaging system. Results As GCA increases, noticeable macular morphological changes occurred and recorded in 96% of infant at 45-46 weeks of GCA. Retinas were gradually vascularized at 41-42 weeks (nasal retina) or 43-44 weeks (area Ⅲ,temporal retina), and pigmented in 84% of infant at 45-46 weeks of GCA. Conclusion Macular morphological patterns, retinal blood vessels and pigments continue to develop in postnatal premature infants.
Objective To observe the dynamic expression of nestin and glial fibrilary acidic protein (GFAP) in the development of retina in rats.Methods In 48 Wistar rats, 24 were divided into 8 groups with 3 rats in each according to their age (1 day, 1 week, and 2, 3, 4, 7, 12, and 20 weeks old). The sagittal freezing sections of the eye were made; nestin/glutamine synthetase (GS) and GFAP/GS were stained by immunofluorescence and were observed under the confocal microscope. Total RNA was extracted from 18 rats which were divided into 6 groups according to the age (1 day, 1 week, and 2, 3, 4, and 12 weeks old) with 3 rats in each. The expression of nestin, GAFA and GS mRNA were detected by realtime quantitative reverse transcription polymerase chain reaction (RT-PCR). Müller cells were cultured from postnatal day 7-12 rats; the expression of nestin and GFAP was detected by immunostaining study. Double immunofluorescence was carried out between nestin/GS and GFAP/GS.Results One day after the birth, nestin positive cells were found in the whole retinal neuroblast layers with elongated retinal progenitor cells; the GFAP positive astrocytes were observed in the inner retina. One week after the birth, Müller glial cells expressed GS and nestin but not GFAP; GFAP positive cells localized in the inner retina.Two to 12 weeks after the birth, the expression of nestin in Müller cells decreased and even disappeared; the expression of GFAP in astrocytes didn't change much. The Müller cells expressed nestin but no GFAP in vitro. The expression of nestin and GFAP mRNA in retina was accordant with the results of immunofluorescence staining.Conclusion In the developing retina, the expression of nestin in Müller cells decreases gradually, and no expression of nestin can be found in adult rats; the expression of GFAP can't be observed in Müller cells in neonatal and adult rats.
Objective To investigate the expression of hypoxia inducible factor 1(HIF1alpha;) in ratsprime; retinae during the embryonic and earlier postnatal period. Methods The retinal expression patterns of HIF-1alpha; protein and mRNA of embryonic day 12 (E12), E16, E20, and postnatal day 1(P1) and P5 rats were determined by immunohistochemical staining and reverse transcriptionpolymerase chain reaction (RT-PCR). Results HIF-1alpha; protein was detected in the neural epithelial layer and the pigment epithelial layer at all those 5 timepoints, with higher expression in the ganglion cell layer and the inner plexiform layer, and seems limited to the ganglion cell layer when re tina became more mature. Embryonic rat retina had higher expression of HIF-1alpha; protein and mRNA than postnatal retina, the difference was significant (P＜0.01）. Conclusion The expression of HIF1alpha; in ratsprime;retina e differs from embryonic to earlier postnatal stages.
Objective To observe the retinal ultrastructure of the human fetal at the age of 9 months, and to investigate the clinical significance of the observation on retinal neuron development during the prenatal period.Methods Four human fetal eyes of 2 fetus at the gestational age of 9 months, including 1 at 35 and the other at 36 weeks, were obtained after termination of pregnancy due to trauma. The gestational ages of the fetus were estimated according to both last menstrual period (LMP) of the pregnant women and the weight/crownheel length of fetus at the delivery. From each eyeball, 4 pieces of retina at the posterior pole were obtained and observed after specimens handling according to the procedure of routine electron microscopy. Eight pieces of retina which were randomly selected from total of 16 pieces of retina in each group were processed and observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Permissions from pregnant women and family members were guaranteed.Results At the gestational age of 9 months, the outer nuclear layer of fetal retina contained 5 to 6 layers of photoreceptor cells (PRC), and sphericallike membrane structures were found outside of the outer limiting membrane (OLM). Among many tightaligned inner segments of PRCs there was zonula adherens of OLM, mitochondrias at inner side of OLM, and cilium at outer side of OLM. Outer segment of PRCs were short and contained a few irregularly arranged disc membrane. Some PRC had a multishaped nucleus in which equal amount of euchromatin and heterochromatin. There were only few and thin axon branches from photoreceptor cells, and very few axons contacted with inner nuclear layer (INL) and no typical synapse was found. The INL contained 4 to 5 layers of cell bodies, in which many cellular nuclear had uneven density of euchromatin and heterochromatin; some were lobulated nucleus with clear karyotheca. In inner plexiform layer (IPL), the nerve cells had small branches, and only little connection among the synapses and few synapse structures were found. Although not many retinal ganglion cells (RGC) existed,RGC had both intact cell membrane and some rough endoplasmic reticulum (RER).The karyotheca of RGC had double-layers structures, and the nucleus was mainly consisted of euchromatin. Internal limiting membrane (ILM) had doublelayer membrane structures, and the wellarranged nerve fiber layer was located at the outer side of ILM, with some micropores on the surface. Conclusions At the gestational age of 9 months, all layers of the human retinal has been formed, but some cell structure and cell connections are not yet mature, suggesting that at this time of period, human retina is still at an important stage of developing and remodeling.
Objective To investigate the degree of retinal development in preterm infants.MethodsFlash electroretinography (ERG) was performed on 25 healthy preterm infants and 25 full-term ones, and the response of rod cells and cone cells and maximal mixed responses were recorded. The delitescence and amplitudes of a-and b-waves and the ratio of amplitudes of b-/a-wave of maximal responses were analyzed. ResultsCompared with the full-term infants, The delitescence of responses of rod cells in preterm infants was statistically longer（t=11.007，P=0.000）but without any significant changes of amplitudes （t=1.836，P=0.069）; statistically longer delitescence (t=2.44, P=0.010; t=10.800, P=0.000) and lower amplitude (t=5804，P=0.000; t=5.809,P=0.000) of a-and b-wave of maximal response were found in preterm infants group. In the response of cone cells, there were significant differences of the delitescence （t=4.444，P=0.000）and amplitude （t=3.819，P=0.000）of a-wave and delitescence of b-wave（t=2.850，P=0.005） between the two groups, and no statistical difference of amplitude of b-wave （t=0.486，P=0.628） between the two groups. The ratio of amplitudes of b-/a-wave of the maximal mixed response was not significantly different between the two groups （t=1.142，P=0.256）.ConclusionsThe development of retinal function is slower in preterm infants than that in full-term ones.(Chin J Ocul Fundus Dis, 2005,21:285-287)
Objective To study the progressive development of the retinas through an observation on the histological changes of the retinas from neonatal mice of different day-ages. Methods The retinas from the mice of 1 to 20 days of age were examined by light microscopy,and from 1 to 3 days,by autoradiography. Results The retinas of the mice below 3 days of age only had the RPE cells layer,the neuroblast layer and the ganglion cell layer.With the increase in dayage,the retinas developed gradually and would be mature in the 20th day. Conclusions The retinas of mice is a kind of immature tissue before the 20th days,so it can be considered as transplantation donors. (Chin J Ocul Fundus Dis, 1999, 15: 174-176)
ObjectiveTo observe the macular morphological development and thickness of retinal layers in infants. MethodsFifty-eight infants (86 eyes) were randomly selected from neonatal intensive care unit. They were divided into 4 groups according to the corrected gestational age, including <32 weeks group (10 cases, 14 eyes), 33 to 36 weeks group (26 cases, 39 eyes), 37 to 41 weeks group (12 patients, 18 eyes) and ≥42 weeks group (10 cases,15 eyes). Twelve health adults (22 eyes) were randomly selected as adult group. All infants and adults underwent a portable optical coherence tomography (OCT) examination, focus on the macular morphology. The thickness of 9 retinal layers at fovea and parafovea (750 μm, 1500 μm from central fovea) were measured, including retinal neurepithelium layer, the inner retina, the outer retina, nerve fiber layer, ganglion cell layer, inner plexiform layer, inner nuclear layer, outer plexiform layer and inner nuclear layer. The correlation between retinal thickness and corrected gestational age was analyzed. ResultsMacular fovea was shallow in early infancy, and then form a mature macular fovea finally with corrected gestational age. The outer retina structure was more mature than the inner retina of infants. With the increase of the corrected gestational age, the following structures gradually developed including the outer limiting membrane (OLM), the junction of inner and outer segment of photoreceptor (IS/OS), the outer segment of photoreceptor/retinal pigment epithelium layer (OS/RPE). The earliest corrected gestational age to detect the OLM, IS/OS, OS/RPE was 32+6, 35, 47+6 weeks respectively. The RPE and choroid layer became thicker gradually. There were no statistical differences between infants group and adults group (P>0.01) for the following thickness measurements, including inner retina at 750 μm parafovea, nerve fiber layer at 1500 μm parafovea, ganglion cell layer at central fovea and parafovea (750 μm, 1500 μm). The thickness of other retinal layers was different between different sites, between different corrected gestational ages, and between infants and adults groups (P<0.01). Correlation analysis found that, except of retinal ganglion cell layer, the thickness of other retinal layers was correlated with the corrected gestational age (P<0.05). ConclusionsMacular fovea is shallow in early infancy, and then form a mature macular fovea finally with corrected gestational age. At infant's early stage, the outer retina of macular is gradually thickening, of which the most obvious variation are the inner nuclear layer and outer nuclear layer. But the development speed of all layers is inconformity.
ObjectiveTo determine the retinal thickness of normal children 3-6 years old and its relationship with the age and gender. MethodsIn a cross-sectional study, 480 eyes of 240 normal preschool children including 115 male and 125 female, ages 3 to 6 years in the urban of Beijing, China were included. The average age was (4.93±0.77) years old. The visual acuity, slit-lamp microscopy and frequency domain optical coherence tomography (FD-OCT, Optvue, Inc. USA) were examined. The retinal thickness of the macular fovea and 500, 750, 1500 μm from temporal and nasal side around the fovea were measured. 32 eyes were excluded from the study because they couldn't cooperate. Pearson correlation analysis was used to determine the correlation between age and macular retinal thickness. Independent samples group t-test was used to compare the differences between boys and girls. ResultsThe mean thickness of macular fovea was (169.10±20.587) μm. The mean macular thickness of boys was significantly higher than girls (t=-4.549, -6.167, -5.492, -5.163, -6.749, -7.494, -6.874; P≤0.001). The mean thickness of 500 μm and 750 μm from nasal side of macular fovea were significantly higher than temporal side (t=5.594, 15.778, 7.678, 18.180; P < 0.001). There was no significant relevance between macular thickness and age. ConclusionsThe mean macular thickness of boys is significantly higher than girls in normal children in the urban of Beijing. There is no significant relevance between macular thickness and age.