Objective：To observe the histochemical changes of retinal photochemical damage in rats. Methods：The changes of retinal ultrastructure were observed.The concentration of malondaldehyde(MDA) was tested and the activity the histochemical change of cytochrome oxidase (CCO) and (Mg ++ -ATPasw) were evaluated on the retnal photochemical damage in SD rats. Results：At the 6th hour after light exposure,the swelling appwared at the nuclei of photoreceptor,the mitochondria of inner segment.The apical microvilli of RPE disappeared and lysosomes increased in RPE.On the 6th day after light exposure,the changes became more obvious.While on the 14th day after light expose the nuclei of photoreceptors and the inner segments renewed but the arrangement of the disk was lose;and the microvilli appeared of the disk was lose;and the microvilli appeared at the tip of RPE.The Activity of CCO and Mg ++ -ATPase decreased and MDA increased in retina at the 6th hour and on the 6th day and they recovered on the 14th day after light exposure. Conclusion：Lipd peroxidation that broke the cell membrane system of photoreceptor which induced changes of the cell ultrastru cture abd the activity of enzyme might relate to pathogenesis in retinal photochemical damage. (Chin J Ocul Fundus Dis,1998,14:38-40)
Objective To investingate the ultrastructural changes of retinal pigment epithelium(RPE) and its permeability in spontaneously hypertensive rats(SHR)and explore the relation between these changes and hypertensive retinopathy.MethodsThe ultrastructure of RPE cells in the SHR aged five,six,seven months wasobserved with transmission electronmicroscope and compared to its normotensive control strain(WKY) with the same age.Then,lanthanum tracer procedures were carried out to investigate pathological changes of the blood-retinal barrier.Results (1)In SHR the main pathological changes involved swelling of mitochondria,enlargement of endoplasmic reticula,decrease of RPE cell infolding,and sparseness of microvilli.These degenerations were more serious in older rats with higher blood pressure.(2)The breakdown of outer blood-retinal barrier with permeation of lanthanum tracers were evident in SHR aged six or seven month,however,in WKY and five-month SHR the traces were prevented from passing by tight junctions.ConclusionThe degeneration of RPE owing to ischemia and anoxia arises in early periosd of hypertensive retinopathy.The pathological changes of ultrastructure and permeability might interact with the damage of visual cells and play a main role in the hypertensive retinopathy.
Objective To investigate the effect of polyethylene glycolbovine hemoglobin (PEG-bHb), which was used as an oxygen carrier in cardioplegic solution, on the protection of isolated rat hearts. Methods The hearts of 32 male SD rats were harvested and transferred to Langendorff circuit. They were divided into 4 groups according to cardiocplegia: St.Thomas group (group A), 1∶2 PEG-bHb group (group B), 1∶4 PEG-bHb group (group C) and 1∶8 PEG-bHb group (group D). After 20min balance period, hearts were perfused with cold (4℃) cardioplegic solutions, and preserved at 30℃ for 60min, then reperfused. Levels of cardiac troponin I (cTn I) and adenosine triphosphate(ATP) contant in coronary effuent were detected, and ultrastructures of myocardium were observed. Results After reperfusion, cTn I contant of group A were higher (F=52.955,Plt;0.05) and ATP contant were lower (F=68.757,Plt;0.05) than those in group B, group C and group D. Myocardial water contant were lower in group B and group C(F=3.048,Plt;0.05). Conclusion PEG-bHb in cardioplegic solutions can provide better myocardial protection during ischemia.
ObjectiveTo investigate the medium and long-term influence of silicon oil versus heavy silicone oil on rabbit retinas.
Methods28 health standard rabbits were randomly divided into A, B and C groups, with 12, 12 and 4 rabbits respectively. All rabbits received routine vitrectomy and tamponade with silicone oil (group A), or heavy silicone oil (group B) or balanced salt solution (group C). After 4, 8, 12 and 24 weeks, the retinal b-wave amplitude was measured by ERG, posterior retinal thickness was measured by optical coherence tomography (OCT). Retinal ultrastructure and tissue morphology were observed by transmission electron microscopy and optical microscopy.
ResultsCompare to group C, the b-wave amplitude decreased at 4 weeks after surgery, and decreased at 8 weeks after surgery for group B, and decreased at 8 weeks after surgery, and decreased at 24 weeks after surgery for group A. The decreases were greater in group B than group A at 8, 12, 24 weeks after surgery, the difference was statistically significant (P < 0.05). The posterior retinal thickness of group A and B was thinner than group C at 24 weeks after surgery (P < 0.05). The decreases were greater in group B than group A, the difference was statistically significant (P < 0.05). Transmission electron microscopy and optical microscopy revealed severe pathological changes of retinal ultrastructure and morphology in group A and B rabbit eyes, at 12 weeks and 8 weeks after surgery respectively. The changes were more severe in group B and group A, including edema and necrosis in cone/rod cells, in disk membranes, mitochondria, cytoplasm, nucleus and other organelles. The morphological changes were also more severe in group B and group A, including degenerations of ganglion cell layer, inner nuclear layer changes. Those changes became more severe when the tamponade time extended.
ConclusionThe heavy silicone influence on visual function, ultrastructures, histomorphology of rabbit retinas is much worse than the silicon oil, and the effect is more significant with its time prolong.
PURPOSE:Investigating on histopathologic changes of the photoreceptors in retinitis pigmentosa.
METHODS:Observation of the photoreceptors of retinitis pigmentosa in 11 eyes among 9 cases using light and electron microscope.
RESULTS: The pathologic changes of the photoreceptors were found to be mostly marded at the equatorial area and less at the periphery,posterior pole and macular region of the retina. In relatively early cases,degeneration and shortening of outer segments,reduction or loss of connecting cilia,stubby inner segments and swollen mitochondria Were the predominant findings. In advanced cases,the inner and outer segments and connecting cilia were diminished with reduction of nuclei in number and disarangement,cellular degeneration and disorganization. The outer limiting membrane adhered to RPE or Bruch membrane. The spaces left over by the above pathologic
changes were replaced by the displaced Muuml;ller cells and their hypertrophic processes. Also there were degeneration of the RPE cells,and some of them might migrate into the retina.
CONCLUSION:Obvious invasions of pathologic processes in photoreceptors of the retina did present in patients with retinitis pigmentosa.
（Chin J Ocul Fundus Dis,1996,12:160-162）
Objective
To study the global and histological changes of myopia and explore its pathogenic mechanism.
Methods
Chicks were reared with monocular suture of eyelid. When myopia had been confirmed by optometry, eyeballs were removed and subjected subsequently to measurement and light and electron microscopies.
Results
Three dimensions in the eyeballs of suture group were all enlarged markedly and the mean diopter was -15.00D. Under the light microscope, rod outer segment elongated and connected With PREC in suture group. With micrometer measure, cartilaginous sclera thickened and retina became thinner. Under electron microscope, rod outer segment elongated and membrane disc was intact. In the cytoplasm of RPEC, the phagosomes containing fractions of the membrane disc of outer segment were remarkably decreased.
Conclusion
Early form deprivation may affect the drop of membrane disc and cause eyeball enlargement; thus, myopia forms.
(Chin J Ocul Fundus Dis,1999,15:20-23)
Objective
To observe the morphological changes of dendrite and soma in retinal ganglion cells (RGCs) which subsisted in early diabetic rats.
Methods
The RGCs of 3-months-course diabetic rats and coeval normal rats were marked by gene gun techniques. To collect RGCs photographs by Leica microscope with Z axis and CCD camera；to observe the changes of diameter, variance of structural features in dendritic field and somata after classification which according to the size and morphology. Thy-1 antibody marks on the retinal RGCs, taking a photograph under fluorescent microscope, counting the changes of retinal RGCs density in early diabetic rat.
Results
In three-month diabetic rats,the density of retinal RGCs was decreased obviously. Morphological changes of RGCs in the dendritic fields were observed with gene gun technique. There was no severe variation in all kinds of the bole of cell dendrite, in which some only showed crispation partially and sparseness also twisting in the dendritic ramus. The mean diameter of dendritic field and soma in class A of diabetic rats was (401plusmn;86) mu;m, the mean diameter of dendritic field in control group was (315plusmn;72) mu;m,compared with each other, there is statistically significant differences (t=21.249，Plt;0.001); the mean diameter of soma in class A of diabetic rats was (24plusmn;6) mu;m, the mean diameter of soma in control group was (22plusmn;5) mu;m, compared with each other, there is no statistically significant differences (t=0.927，Pgt;0.05); the mean diameter of dendritic field and soma in class B of diabetic rats were (170plusmn;36)、(14plusmn;2) mu;m respectively, in control group were (165plusmn;36)、(16plusmn;2) mu;m, the mean diameter of dendritic field and soma in class C of diabetic group were(265plusmn;78)、(17plusmn;5) mu;m respectively, in control group were (251plusmn;57)、(17plusmn;4) mu;m , compared with each other, there are on statistically significant differences(t=1.357，0.798，0.835，1.104，Pgt;0.05).
Conclusions
In short-term diabetes, the survived RGCs show good plasticity in adult diabetic rats, especially in class A. The changes of dendrites were more sensitive than the soma, which could be the leading index of the morphologic changes of RGCs in the early stage. The good plasticity showed by the RGCs and the time window from changing in dendrite to cell death provide us many evidences not only for the research but also for the nerve protection in clinic.
(Chin J Ocul Fundus Dis,2008,24:249-254)
Objective
To observe the enzymic histochemical and ultrastructral changes of cryopreserved human retina.
Methods
To compare the activity of lactate dehydrogenase (LDH)， succinate dehydrogenase (SDH) and ATPase in cryopreserved retina with those in fresh retina and to observe the histological and ultrastructural changes of cryopreserved retina.
Results
There was no statistical difference between the activity of LDH，SDH and ATPase in fresh and in cryopreserved retina. Histologically, in the cryopreserved retina, fluid in neural fiber and outer plexiform layers, as well as in cone and rod layer, was sligthly more than normal. The ultrastructure is normal except that the mitochondria was swollen in different degree.
Conclusion
Cryopreservation may be an effective method for keeping the retinal cells alive for a long period and might free the transplantation from dependance on aviability of fresh dornor tissue.
(Chin J Ocul Fundus Dis，2000，16：139-212)
Objective
To investigate whether recombinant human serum albumin (rHSA) can replace traditional B27 as a basic medium for differentiation of human pluripotent stem cells (hPSCs) into cardiomyocytes.
Methods
hPSCs were seeded at a cell density of 1.2×104/cm2; until up to 75% confluency hPSCs were induced by differentiation medium containing various concentration of rHSA (0, 50, 100, 200 g/L). Light microscope and fluorescence microscope recorded the whole process of stem cells differentiating into myocardium. Flow cytometry was used to detect the cardiac differentiation efficiency at different concentrations of rHSA. Immunofluorescence staining was used to detect the cardiac specific protein α-actinin and troponin T (cTnT) and electron microscope to observe the ultrastructure of human pluripotent stem cell-derived cardiomyocytes (hPSC-CM) and beating rates of hPSC-CMs response to drugs.
Results
A large number of spontaneous beating cardiomyocytes were observed 9 days after induction and differentition. The percentage of colonies showing beating cardiomyocytes was 60.4% at the concentration of 200 g/L of rice derived-rHSA. Beating cardiomyocytes were α-actinin and cTnT positive. Ultrastructural analysis showed scattered sarcomeres and mitochondrial. hPSC-CMs were dose-dependent on isopropyl adrenaline and verapamil.
Conclusion
Using such simple media to differentiate hPSCs into functional cardiomyocytes is cost-effective and highly efficient, and can be used in the clinical research.
Objective
To observe the ultrastructural characteristics of human retinal progenitor cells cultured in vitro.
Methods
Six 5-month-old human fetuses（12 eyes）without eye diseases were selected.
Retinal
progenitor cells from the retina of one eye of each fetus were cultured in vitro，and observed by transmission electronic microscopy（TEM）; while those from the other eye were directly observed by TEM. Results Abundant heterochromatin were found in the karyon of 5-month embryonic retinal neuroepithelial cells，and the figure of the karyons was irregular.A few scattered initial cells were seen in retinal neuroepithelial layer with large karyon，smooth surface，abundant euchromatin，and distinct nucleolus.The human retinal progenitor cells cultured in vitro had the same ultrastructural characteristics as the initial cells:with huge karyon which almost occupied the whole cell，little cytoplasm，distint nucleolus，abundant euchromatin，and little heterochromatin.The cells clung to each other in the neural globoid cell mass.The size of the outer cells was large，and karyokinesis could be found.
Conclusion
The cultured human retinal progenitor cells are provided with the same ultrastructure characteristics as the initial cells.
(Chin J Ocul Fundus Dis, 2006, 22: 185-187)
