ABSTRACT
Background Normal ultrastructure is the anatomical basis of retinal pigment epithelial(RPE) cells to perform normal physiological function.At present the precipitation method is often used to detect the ultrastructure of RPE cells with transmission electron microscopy(TEM).Objective The aim of this study was to explore a simple and feasible approach to examine the ultrastructure of human embryonic stem cell-derived retinal pigment epithelial (hESC-RPE) cells.Methods hESCs were induced and differentiated into RPE cells by the spontaneous differentiation method,and the expressions of microphthalmia associated transcription factor MITF and paired-box gene 6 (PAX6),specific protein of RPE cells,in the cells were detected by immunofluorescence assay.hESC-RPE cells were inoculated into Transwell filter,and the ultrastructure of the cell sheet was examined under the TEM.Then the ultrastructure of the cell sheet specimens was compared with those of hESC-RPE cells from cell precipitation and RPE cell specimens of 90-day-old Long Evans rats.Results MITF and PAX6 were positively expressed in hESC-RPE cells.The normal ultrastructure were visible in the RPE cells of rats under the TEM,including apical microvilli,polarized melanin granules,cellular nucleus,basement membrane and intercellular junctions,and the ultrastructure of hESC-RPE cell sheet on Transwell was similar to the RPE cells in rats.However,only scatter melanin granules,nonpolar nucleus and scanty microvilli were observed under the TEM in the hESC-RPE cells by cell precipitation method.Conclusions Without digestion process,hESC-RPE cell sheet on Transwell can retain the normal ultrastructure of hESC-RPE cells under the TEM,with a more simple and reliable advantage.
ABSTRACT
<p><b>OBJECTIVE</b>To study the oxidative stress induced by consumption of mercury-contaminated rice in rats, and to assess the possible public health risk of mercury contamination in Wanshan mining area.</p><p><b>METHODS</b>Sprague Dawley rats were fed the mercury-contaminated rice produced from Wanshan area for 90 days. The antioxidant status and the free radicals in rat serum were evaluated.</p><p><b>RESULTS</b>High mercury accumulation in organs of rats fed the mercury-contaminated rice confirmed the server pollution of mercury in Wanshan mining area. The intensity of electron spin resonance (ESR) signal increased by 87.38% in rats fed the rice from Wanshan compared with that in the control rats fed the rice from Shanghai, suggesting that chronic dietary consumption of rice from mercury mining area could induce an aggravation of free radicals. Feeding the mercury-contaminated rice was associated with significant decreases in the antioxidant enzymatic activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and concentration of serum nitric oxide (NO), but it had no effect on serum nitric oxide synthase (NOS) activity. Feeding the mercury-contaminated rice raised the level of serum malonyldialdehyde (MDA), indicating the occurrence of oxidative stress.</p><p><b>CONCLUSION</b>The long-term dietary consumption of mercury-contaminated rice induces the aggravation of free radicals and exerts oxidative stress.</p>
Subject(s)
Animals , Rats , Brain , Metabolism , China , Environmental Pollutants , Pharmacokinetics , Toxicity , Food Contamination , Free Radicals , Blood , Glutathione Peroxidase , Blood , Industrial Waste , Kidney , Metabolism , Liver , Metabolism , Malondialdehyde , Blood , Mercury , Pharmacokinetics , Toxicity , Methylmercury Compounds , Pharmacokinetics , Toxicity , Nitric Oxide , Blood , Nitric Oxide Synthase , Blood , Oryza , Oxidative Stress , Rats, Sprague-Dawley , Superoxide Dismutase , BloodABSTRACT
<p><b>OBJECTIVE</b>Mercury (Hg), as one of the priority pollutants and also a hot topic of frontier environmental research in many countries, has been paid higher attention in the world since the middle of the last century. Guizhou Province (at N24 degrees 30'-29 degrees 13', E103 degrees 1'-109 degrees 30', 1 100 m above the sea level, with subtropical humid climate) in southwest China is an important mercury production center. It has been found that the mercury content in most media of aquatics, soil, atmosphere and in biomass of corns, plants and animals, is higher than the national standard. The present study aims to explore the influence of mercury pollution on the health of local citizens.</p><p><b>METHODS</b>The effect of rice from two mercury polluted experimental plots of Guizhou Province on the expression of c-jun mRNA in rat brain and c-jun protein in cortex, hippocampus and ependyma was observed using reverse transcription polymerase chain reaction (RT-PCR) and immunocytochemical methods.</p><p><b>RESULTS</b>The results showed that the mercury polluted rice induced expression of c-jun mRNA and its protein significantly. Selenium can reduce Hg uptake, an antagonism between selenium and mercury on the expression of c-jun mRNA and c-jun protein.</p><p><b>CONCLUSION</b>c-jun participates in the toxicity process of brain injury by mercury polluted rice, the expression of c-jun mRNA in brain, and c-jun protein in rat cortex and hippocampus can predict neurotoxicity of mercury polluted rice. People should be advised to be cautious in eating any kind of Hg-polluted foods. To reveal the relationship between c-jun induction and apoptosis, further examinations are required.</p>