Inhibition of corneal fibrosis by Smad7 in rats after photorefractive keratectomy / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Haze or corneal subepithelial fibrosis is one of the common complications after refractive surgery procedures, such as photorefractive keratectomy (PRK), laser epithelial keratomileusis, and epipolis laser in situ keratomileusis, which would result in refractive regression, decreased visual quality, and corneal opacification. Haze directly resulted from corneal fibrosis mediated by transforming growth factor β (TGFβ). Smad7, an inhibitory Smad, can inhibit TGFβ signal transduction. Recently, the effects of Smad7 on the inhibition of fibrosis in several organs have been studied, while little is known about the effects on cornea after PRK. This study was aimed to determine the effects of lentiviral-mediated Smad7 gene expression on corneal fibrosis in rats after PRK.</p><p><b>METHODS</b>Four different experimental groups were established using right eyes of Sprague-Dawley rats. Thirty-two eyes underwent de-epithelialization only and served as a sham operation group (group 1). Ninety-six eyes underwent PRK operation and were further divided into group 2 (the PRK group) without lentivector administration, group 3 (the Lv-blank group) with control lentiviral vector without Smad7 administration, and group 4 (the Lv-Smad7 group) with Smad7 expressing lentiviral vector Smad7 administration. At 1 day, 1 week, 1 month, and 3 months after PRK, the transfection efficiency was determined by measuring the fluorescence signal as well as Smad7 protein and mRNA levels. Corneas were further processed for immunoblotting to assess the phosphorylation of Smad2 as a downstream event of TGFβ/Smad signaling. The expression of fibrotic markers, such as α-smooth muscle actin (α-SMA), Type III collagen (collagen III), and cell cycle-related marker Ki67, was measured by quantitative real-time reverse transcription polymerase chain reaction (RT-PCR).</p><p><b>RESULTS</b>Lentivirus-mediated exogenous Smad7 gene expression in rat corneal tissue resulted in reduced activation of TGFβ/Smad signaling caused by downregulation of phosphorylation of Smad2. Smad7 also downregulated the expression of TGFβ2. Markers of cell proliferation and fibrosis, including Ki67, α-SMA, and collagen III, were inhibited by Smad7 up to 3 months after PRK operation.</p><p><b>CONCLUSION</b>Smad7 gene transfer inhibits fibrogenic responses of cornea in rats after PRK.</p>

Effects of different wave-length lights on proliferation and secretion of growth factors in human retinal pigment epithelium cells / 中华实验眼科杂志

BackgroundThe study of myopia development is always the hotspot worldwide. Recently,scientist found that some growth factor secreted by retinal nerve epithelium cells and retinal pigment epithelium(RPE)cells are associated with the development of myopia. Whenever, the absorption of RPE cells to different wave-length lights is different. ObjectiveThis study was to investigate the effects of different wave-lengths lights on the proliferation of human RPE cells, and explore the influence of different wave-lengths lights on RPE cells secreting hepatocyte growth factor(HGF) ,basic fibroblast growth factor(bFGF) and transforming growth factor-β(TGF-β).Methods The fourth to fifth passages of human embryonic RPE cells were exposed to blue light( λ =480 nm),red light( λ =775 nm) and white light. The cells of control group were harvested in normal condition. The proliferation and growth of RPE cells were assayed by MTT,and the ultrastructure of cells was examined under the transmission electron microscopy at 48 hours after light exposure of RPE cells. Enzyme linked immunosorbent assay(ELISA) was adopted to determine the concentrations of HGF,bFGF and TGF-β in the culture medium in 12,24,48,72 hours. The expression of HGF mRNA in RPE cells was detected by RT-PCR. This study was approved by Ethic committee of Fudan University. ResultsThe A490 values of the cells exposed to blue light,red light,white light and white light were 0. 0218±0. 0014 ;0. 0353±0. 0025 ;0. 0371 ±0. 0024 and 0. 0445 +0. 0046 respectively with the significant difference among 4 groups ( F =12. 579, P＜0.05 ), and A490 value in blue light group, red light group were significantly lower than that of the control group ( t =2.043 ; t =2.024, P＜0.05 ). ELISA showed that the concentrations of HGF and TGF-β in culture medium were evidently elevated as the prolongation of light exposure in various light exposure groups in 72 hours(HGF) and 48 hours(TGF-β) compared with 12 hours with a predominating rise in the control group. The statistically significant differences were found in the concentrations of HGF and TGF-β between control group and blue light group or red light group in the( all P＜0. 05 ). The bFGF level was decreased with the time increase of various light exposure with the significant differences in 72 hours compared with 12 hours( P＜0.05 ). RT-PCR revealed the considerable difference about expression of HGF mRNA in RPE cells among these four groups( P＜0. 05 ), and the lest expression in HGF mRNA was in the blue light group compared with control group( t =3. 972,P＜0.05 ). Thinning of the chromatin, decreasing of organelle and loss of cellular membrane were seen in the blue light group, but no obvious change of ultrastructure of human embryo RPE cells was found in the ret and white light groups. ConclusionsThe irradiation of different wave-length light can effect the growth and proliferation and secretion of HGF,bFGF and TGFβ in human RPE cells in vitro,implying myopia formation is associated to exposure of different wave-length light.

Influence of long-time illumination of monochromatic light on density of cones and opsin expression in guinea pig / 中华实验眼科杂志

Background The visual system of animal have to optimally adjust in various environmental conditions in order to obtain stable and effective visual funetion.However,the color vision system of animals which encounter uncertainty of spectral signals should be plastic.Whether the densities of various cones and expression of opsins change with long-time spectral deprivation is unclear.Objective This study was to investigate the changes of cone density as well as the expression of corresponding opsin and mRNA following the long-term illumination of monochromatic light.Methods Thirty 3-day-old guinea pigs were randomized into 3 groups and exposed tO the 530 nm green light,400 nm purple light and white light for consecutive 8 weeks respectively.The flat-mounted retinal sample was prepared and divided into dorsal zone,ventral zone and mixed zone anatomically according to the distribution of difierent light-sensitive cone.The changes in density of cone cells sensitivited to different colored light were detected by single-1abel or double-label immunocytochemistry.The levels of opsin and its mRNA were determined using Western-blot and real-time PCR respectively.Results The density of green-sensitivity cones was significantly different in the dorsal zone of retina among green light group,purple light group and white light group (F=234.28,P<0.01).Compared with white light group,the density of green-sensitive cones in dorsal retina of green light group was obviously higher but that of purple light group wag evidently lower(q=389.68,P<0.01；q=67.11,P<0.01).No significant difference was found in the density of purple-sensitive cones in the ventral zone of retina among green light group,purple light group and white light group(F=3.14,P>0.05).The density of coexpression of the mixed cone cells was increased in green light group(q=157.55,P<0.01)but decreased in purple light roup (q=254.85,P<0.01)in comparison with white light group.The expression levels of green-opsin and green-opsin mRNA in green light group was significantly elevated(q=184.45,P<0.01；q=4.71,P<0.05),but those of purple light group were evidently declined(q=5.87,P<0.05；q=346.66,P<0.01)in comparison with white light group.There was no statistically significant differences were found in the expression of purple-opsin and its mRNA among all the groups(F=1.24,P>0.05；F=3.27,P>0.05).Conclusion After the exposure of long-time monochromatic light illumination,monochromatic cones density and its opsin in guinea pig occur the corresponding alteration to gain good spatial vision as a compensatory reaction.These outcomes imply that there is some plasticity during the development of color vision.The increase of green-sensitive cones might be from the differentiation of coexpression cones in transition region.

Relationship between best corrected visual acuity and refraction parameters in myopia / 法医学杂志

OBJECTIVE@#To explore the relationship between best corrected visual acuity (BCVA) and refraction parameters in myopia.@*METHODS@#Two thousand two hundred and seventy-four patients (4245 eyes) with different degrees of myopia were collected. Their BCVA, diopter of spherical (DS), diopter of cylinder (DC), astigmatism axis, axial length (AL) and corneal thickness were detected. The influence of those parameters on BCVA was studied and the mathematical model of the relationship between BCVA and other parameters including the age and gender of patients was established.@*RESULTS@#The logistic regression analysis showed that there were correlations between the BCVA (y) and DS (x1), DC (x2), gender (x3), AL (x4), corneal thickness (x5), astigmatism axis (x6) and age (x7) (P<0.05): y=0.580 6-0.034 0 x1-0.046 8 x2+0.056 5 x3+0.016 5 x4+ 0.0007 x5+0.000 2 x6-0.005 8 x7.@*CONCLUSION@#For people with myopia, age, gender and corneal thickness have small effect on BCVA, while the DS, DC, AL and astigmatism axis have significant effect on BCVA. The BCVA would decline following the extension of DS, DC and AL. It is helpful to assess the vision of myopia by analyzing the refraction parameters comprehensively.

Expression of Smad7 inhibits fibrogenic responses of keratocytes to transforming growth factor β2 / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Transforming growth factor β (TGFβ) is one of the most important growth factors in the development of fibrosis and scarring on cornea. Smad7, an inhibitory Smad, can inhibit TGFβ signal transduction. In recent years, effects of lentiviral-mediated Smad7 on inhibition of fibrosis on some organs have been studied, while little is known about the effects on cornea. This study aimed to determine the effects of lentiviral-mediated Smad7 gene expression on keratocyte proliferation and fibrosis induced by TGF β2 in vitro.</p><p><b>METHODS</b>Keratocytes were cultured from corneal tissue isolated from Sprague-Dawley (SD) rats and transfected with Smad7 expressing lentiviral vector (Lv-Smad7) or non-functioning control vector (Lv-blank). Following the exposure to TGFβ2, keratocytes were processed for immunoblotting to assess the phosphorylation of Smad2 as down-stream event of TGFβ/Smad signaling. Expression of fibrotic markers α-smooth muscle actin (α-SMA), type III collagen (collagen III) were measured by Western blotting and quantitative real time polymerase chain reaction (PCR). Overall cell proliferation was determined by 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and the expression of cell cycle-related marker Ki67 at both mRNA and protein levels.</p><p><b>RESULTS</b>The Smad7 gene transfer suppressed TGFβ/Smad signaling in keratocytes by down-regulating phosphorylation of Smad2. Markers of cell proliferation and fibrosis including Ki67, α-SMA, collagen III were inhibited by introduction of Smad 7 into TGFβ exposed keratocytes. Consequently, the rate of cell proliferation was attenuated.</p><p><b>CONCLUSION</b>Smad7 gene transfer inhibited fibrogenic responses of keratocytes to TGFβ2.</p>

Effects of age on ocular anterior segment dimensions measured by optical coherence tomography / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Older subjects tend to have smaller ocular anterior segment. The present study aimed to measure anterior segment dimensions with optical coherence tomography (OCT) and quantitatively assess the effect of age and other factors.</p><p><b>METHODS</b>Anterior segment OCT images were obtained in normal subjects residing in the greater Los Angeles area. Four line scans were acquired at the 90°, 45°, 0° and 135° meridians of each eye. Computer calipers acquired anterior segment dimensions of corneal diameter, anterior chamber width, corneal vault and anterior chamber depth on OCT images. Measurements from 4 meridians were averaged. Axial length and corneal power were measured by partial coherence interferometry. Univariate and multivariate analyses were performed to assess correlations.</p><p><b>RESULTS</b>Sixty-six eyes of 33 normal subjects (aged 22 - 65 years, 19 Asians, 14 Caucasians) were enrolled. For every 1 year of age, corneal diameter was 0.033 mm narrower (P < 0.01), anterior chamber width was 0.031 mm narrower (P < 0.01), corneal vault was 0.016 mm lower (P < 0.01), and anterior chamber depth was 0.025 mm lower (P < 0.01). Asian eyes had smaller corneal diameter (P = 0.035) and anterior chamber width (P = 0.015) compared with those of Caucasian eyes. Body height showed positive correlation with corneal diameter (0.039 mm per centimeter of height, P < 0.01) and corneal vault (0.024 mm per centimetre of height, P < 0.01). Gender did not have an independent effect on anterior segment dimensions.</p><p><b>CONCLUSIONS</b>Anterior segment dimensions were smaller in older subjects. Age-related changes may affect the tolerability of long-term implants such as phakic intraocular lens.</p>

Effect of pirenzepine ophthalmic solution on form-deprivation myopia in the guinea pigs / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Nonselective muscarinic receptor antagonist, atropine, was believed to inhibit myopic progression. The purpose of this study was to determine the efficacy, through topical administration, of the M1-selective muscarinic antagonist pirenzepine in preventing experimentally induced form-deprivation myopia in guinea pigs.</p><p><b>METHODS</b>Fifty-three guinea pigs, which underwent monocular deprivation with their eyelids sutured, were divided into 6 groups. Three groups were treated with 1%, 2% or 4% pirenzepine ophthalmic solutions; the fourth group with atropine; the fifth with saline and the last group left untreated. Ocular refraction, in vivo biometric measurements and wet eye weight were collected before and after the experiment. All the eyes were finally enucleated for histopathological examination to evaluate the possible toxic effects on ocular structures.</p><p><b>RESULTS</b>Animals untreated or treated with saline produced (-2.31+/-1.47) D and (-2.25+/-0.88) D of axial myopia respectively. Those treated with 1% pirenzepine ophthalmic solution produced relative myopia of (-1.63+/-0.48) D, and those under the treatment of 2% and 4% pirenzepine ophthalmic solution only developed a relative myopia of (-0.89+/-0.42) D and (-0.70+/-0.41) D (F=9.56, P<0.05). The significant reduction in myopia in 2% and 4% pirenzepine treated animals was caused by significantly less vitreous chamber elongation and axial elongation of the deprived eyes [2% group: (0.009+/-0.052) mm, 4% group: (0.006+/-0.078) mm] when compared with untreated, saline treated or 1% pirenzepine treated guinea pigs (0.057+/-0.056) mm, (0.064+/-0.053) mm and (0.033+/-0.035) mm, respectively]. Histological examinations revealed no obviously toxic effects on the eyes treated with pirenzepine.</p><p><b>CONCLUSION</b>Topical administration of the M1-selective muscarinic antagonist, pirenzepine, can prevent induced form-deprivation myopia in guinea pigs by inhibiting axial elongation without obvious damage to ocular tissues.</p>