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AIM: To examine the effects of salidroside on choroidal thickness, hypoxia-inducible factor-1α(HIF-1α), dopamine(DA)and its D1 receptor expression in guinea pigs with lens-induced myopia(LIM).METHODS: A total of 18 two-week-old guinea pigs were randomly divided into the normal control(NC)group, the LIM group, and the LIM + salidroside(LIM+SA)group, with 6 guinea pigs in each group. The guinea pigs in the NC group were fed normally and intragastrically administered with 2 mL/d saline; those in the LIM group wore a -5D lens in front of their right eyes to establish a myopia model, then they were intragastrically administered with 2 mL/d saline. Finally, those in the LIM+SA group wore glasses along with intragastric administration of 2 mL/d salidroside at a dose of 100 mg/kg. The refraction, axial length, and choroidal thickness of guinea pigs in each group were measured 4wk following the establishment of the model. In addition, the relative mRNA expression and protein content of HIF-1α in the choroid and retina of guinea pigs in each group were detected by real-time quantitative PCR(qPCR)and immunohistochemistry(IHC). Finally, the DA concentration and its D1 receptor expression were detected by enzyme-linked immunosorbent assay(ELISA)and Western blot.RESULTS: At 4wk after model establishment, guinea pigs of LIM group and LIM+SA group exhibited increased negative refraction of the right eye, prolonged axial length, and decreased choroidal thickness compared to the NC group. The relative mRNA expression and protein content of HIF-1α in the choroid and retina of the guinea pigs increased. The concentration of DA and the expression of its D1 receptor both decreased. Moreover, compared to the LIM group, the diopter of the right eye of guinea pigs in LIM+SA group significantly reduced, the axial length was shorter, the thickness of choroid increased, the relative mRNA expression and protein content of HIF-1α in the choroid and retina decreased and the concentration of DA and the expression of its D1 receptor both increased.CONCLUSION: Salidroside can delay myopia progression in myopic guinea pigs by affecting choroidal thickness and the expression of HIF-1α, DA and its D1 receptor.
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@#AIM:To observe the changes of the vessel density of choriocapillaris in lens-induced myopia in guinea pigs, and to explore choroidal endothelin-1(ET-1), endothelin receptor A(ETAR)and receptor B(ETBR)expression changes and the effect of electroacupuncture. <p>METHODS: Fifty-four guinea pigs were randomly divided into normal control(NC), lens-induced myopia(LIM)and LIM+electroacupuncture(LIM+EA). The NC group was fed normally without intervention and the right eye in LIM group and LIM+EA group was coverd with a -6.00D lens to establish a myopia model. At 2 and 4wk, the refraction, axial length and the vessel density of choriocapillaris in groups were measured. The expression and protein content of ET-1, ETAR and ETBR mRNA in groups were detected by the real-time fluorescent quantitative PCR(quantitative polymerase chain reaction, q-PCR), enzyme-linked immunosorbent assay(ELISA)and immunohistochemistry. <p>RESULTS: At 2 and 4wk, compared with the the NC group, refraction and axial length in LIM group and LIM+EA group had significantly increased(all <i>P</i><0.001). Compared with the LIM group, the refraction and axial length in LIM+EA group were decreased(all <i>P</i><0.05). At 2 and 4wk, compared with the NC group,the vessel density of choriocapillaris was decreased(<i>P</i><0.001)and the ET-1, ETAR and ETBR mRNA and protein levels in choroid were increased(all <i>P</i><0.05)in LIM group. At 2 and 4wk, compared with the LIM group,the vessel density of choriocapillaris was decreased(<i>P</i><0.01)and the ET-1, ETAR and ETBR mRNA and protein levels in choroid were increased in LIM+EA group.<p>CONCLUSION:In LIM guinea pigs, the choroidal blood flow decreased with the increased of refraction and axial length, which may affect ET-1 and its receptors through vascular shear force during the development of myopia. At the same time, electroacupuncture can improve choroidal blood flow through neuromodulation and affects the vascular shear stress to down-regulate the content of ET-1 and its receptor to delay the development of myopia.
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Objective To investigate the effects of amphiregulin antibody on the axial length,diopter and posterior sclera thickness in eyes of bilateral lens-induced myopic guinea pigs.Methods A total of 60 healthy three-colored short-hair guinea pigs were randomly divided into 5 groups:myopic model group,low dose group,medium dose group,high dose group and normal control group,12 rats in each group,and both eyes of the guinea pigs in the former four groups were induced by-10 D lens,while the normal group did not make any treatment.After wearing of goggles for 2 weeks,the right eyes of guinea pigs were intravitreally administrated with 5 μg,10 μg,20 μg anphiregulin antibody for the low,medium and high dose group,respectively.At the same time,the left eyes of these groups were given the same dose of Ringer' s buffer (buffer group).Continuous wearing of the lenses before and after injection of antibody was allowed.Diopter and axial length of guinea pigs were measured before wearing of the lenses,2 weeks after wearing lenses and 5 weeks after the experiment (after 3-times injections of antibody).Moreover,the thicknesses of retina,choroid and sclera in the posterior pole were detected by PAS staining.Finally,the expression of amphiregulin and EGFR mRNA and protein was detected by real time quantitative PCR and immunofluorescence.Results After 2 weeks of lens induction,the axial length of the myopic model group increased,but the diopter decreased when compared with the normal control group,and the differences were statistically significant (both P ＜ 0.05).Compared with the buffer group,after intravitreal injection of amphiregulin antibody,the axial length in the low,medium,and high dose groups decreased,while the diopter increased,and the scleral thickness at the posterior pole increased significantly in a dose-dependent manner,with statistically significant differences (all P ＜ 0.05).However,there was no significant change in retinal thickness at the posterior pole of all groups.Real-time quantitative PCR and immunofluorescence showed the expression of amphiregulin mRNA and protein in the retina was upregulated the myopic model group and buffer group,but downregulated in the high,medium,and low dose groups.Furthermore,when compared with the buffer group,the expression level of epidermal growth factor receptor in the retina of the low dose group was decreased (t =2.606,P =0.022),but there was no significant difference in the other groups.Conclusion After injection of amphiregulin antibody into the eyes of bilateral lens-induced myopic guinea pigs,the diopter increases,but the axial length is significantly shortened,and the posterior sclera is thickened,which may involve a decrease in the expression of amphiregulin.
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Myopia has become a common disease all over the world,affecting the public quality of life and endangering public health.Exploring the pathogenesis is helpful for the prevention and treatment for myopia.However,the pathogenesis of myopia is still not clear,which makes it a hotspot and nodus.From the 1970s,the research on myopic animal models has made great breakthrough.It has provided valuable evidences and hint for mechanism research from the perspective of molecular mechanism,signal pathway,drug intervention,etc.In this paper,the research progess on common myopic animal models and pathogenesis will be reviewed.
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Myopia is one of the most common ocular problems,which causes visual dysfunction.The prevalence of myopia is increasing,while the prevention and treatment have made no breakthrough because the pathogenesis and mechanism of myopia remains unclear.Certain kinds of molecules were reported to play a role in myopia,such as dopamine,retinoic acid,glucagon,ZENK (Zif269、EGR-1、NGFI-A or Krox-24) etc.As a derivative of vitamin A,retinoic acid is the final metabolite of retinaldehyde,which combines to opsin in the photoreceptor cells on retina.Previous studies demonstrated that retinoic acid from choroid and retina plays significant roles in the development of myopia,which affects different molecules related to myopia development,including transforming growth factor-β,glycosaminoglycan,matrix metalloproteinase (MMP)-2 and tissue inhibitor of metalloproteinase (TIMP)-2.Based on the synthesis,mechanism and effects of the retinoic acid in the eye,this paper describes the new progress of retinoic acid in experimental myopia,including form deprivation myopia,defocus induced myopia and monochromatic myopia,hence offers new clues for the research on the mechanism of myopia.
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Background Retinal retinoic acid (RA) plays an important role in the formation of the lensinduced myopia.However,it is not clear how RA transfer the myopic signal to choroid throughout the retinal pigment epithelium (RPE) barrier.Objective The aim of this study was to investigate the effect of all-trans retinoic acid (atRA) on the barrier of RPE in lens-induced myopic eye of guinea pig.Methods Thirty left eyes of 30 21-dayold clean guinea pigs were randomized into normal control group and the model group.The models of out of focus were induced by covering of-6.00 D concave lens on the left eyes for 15 days.Radius of corneal curvature was measured using corneal curvimeter,and diopeter of the guinea pig was examined by mydriatic optometry.The length of ocular axis was detected by A-sonography.The animals were sacrificed and the retinas of the left eyes were isolated for the culture and passage of RPE cells.The third generation of cells were incubated Millcell-PET microporous film,and atRA at the concentration of 1 × 10-6,1 × 10-7,1 × 10-8 and 1 × 10-9 mol/L was added to the micropore respectively for 12 hours,and the micropores with equal-solvent served as negative control group.Methyl thiazolyl tetrazolium (MTT)colorimetric method was used to detect the survival rate of the cells.Subsequently,the transepithelial electrical resistance (TER) of the monolayer cells was determined with CN10-EVOM2 resistance measuring meter.The vesicular transport change of RPE membrane in different groups was evaluated by FM1-43 fluorescence staining.Results The mean diopter was (-2.20±0.95) D in the models,and that in the controls was (+ 1.15 ±0.30) D,with a significant difference between them (t =14.57,P＜ 0.01).The axial length was (8.24 ± 0.09) mm in the models and it was significantly longer than (7.81±0.05) mm in the controls (t=17.20,P＜0.01).RPE cells grew well to form a monolayer in Millcell culture pool after one week.After 24 hours of the atRA treatment,the survival rate of RPE cells reduced gradually with the increase of atRA concentration with the highest rate in the 1 × 10-9 mol/L atRA group (93.3 ％) and followed by the 1 × 10-8 mol/L atRA group (88.2％).More than half of the cells dead in the 1 × 10-6mol/L and 1 × 10-7mol/L atRA groups (53.8％ and 47.1％).Significant differences in the TER value and fluorescence staining intensity of the cells were seen among the various groups (F =43.89,P =0.00 ; F =26.13,P =0.00),with the maximal values in the 1 × 10-8mol/L atRA group.The FM1-43 fluorescence located on the cellular membrane and cytoplasm.Conclusions AtRA can increase the functional state of tight junction and vesicular transport,which regulated the RPE cell barrier in the guinea pig.
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Objective To investigate the effect of basic fibroblast growth factor(bFGF)on the apoptosis of scleral cells in the posterior pole in lens-induced myopia of guinea pigs and to discuss the mechanism of bFGF in inhibiting the formation of myopia. Methods Four-week-old cleaning healthy guinea pigs were randomly divided into the control group,LIM group,LIM+PBS group, LIM+the bFGF 100 ng group,LIM+the bFGF 500 ng group,LIM+the bFGF 1 000 ng group,15 in each.Except the control group, the right eye of guinea pig in other groups wore-10 D concave lens for 7 days and then different concentration of bFGF or PBS were injected into the vitreous cavity,3 days later injected again.After 15 days of-10 D concave lens treatment,the eyeballs were removed and the apoptotic cells in the scleras were determined by electron microscopy,TUNEL technique and flow cytometry.The proliferation of scleral cells in the posterior pole were determined by Ki-67 immune histochemistry stain.Results Compared with the control group,the significant differences were detected in the right eyes of LIM group(P