AIM:To study the efficacy difference between formdeprived myopia(FDM)and lens-induced myopia(LIM),the degree of myopia,axial length and pathological changes of the posterior sclera from guinea pigs were evaluated.METH...AIM:To study the efficacy difference between formdeprived myopia(FDM)and lens-induced myopia(LIM),the degree of myopia,axial length and pathological changes of the posterior sclera from guinea pigs were evaluated.METHODS:Four-week pigmented guinea pigs were randomly assigned into 3 groups,including normal control(n=6),FDM group with monocular cover(n=11)and LIM group with monocular-7D lens treatment(n=11).FDM group was form-deprived while LIM group was lens-induced for 14d.Refractive error and axial length were measured prior to and post treatment,respectively.Morphological changes of sclera were examined using both light and electronic microscopes.RESULTS:After 14d treatment,refractive errors for FDM group and LIM group were-3.05±0.71D and-2.12±1.29D,respectively,which were significantly more myopic than that of normal controls and fellow control eyes(P【0.01).As for axial length,it was 7.93±0.03 mm for FDM group and 7.89±0.06 mm for LIM group,which were significantly longer than both normal and fellow controls(P【0.01).With respect to both refractory error and axial length,the differences between FDM group and LIM group were not significant(P】0.05).Under light microscope,both FDM group and LIM group showed thinned sclera,disarrangement of fibrosis and enlargeddisassociation between fibers.Consistently,ultrastructural examination showed degenerated fibroblasts and thinned fibers in posterior sclera.CONCLUSION:Following two weeks of myopia induction in guinea pigs,with regard to the degree of myopia,axial length and pathological alterations,there was no significant difference between FDM and LIM models.Therefore,FDM and LIM are equally effective and useful as a model of experimental myopia and guinea pigs are ideal animals for induction of experimental myopia because their high sensitivity to both formdeprivation and lens-induction.展开更多
AIM:To evaluate the effect of posterior sclera collagen cross-linking induced by riboflavin-ultraviolet A(UVA)on form-deprived myopia in guinea pigs.METHODES:Twenty-five pigmented guinea pigs of 3-week-old were random...AIM:To evaluate the effect of posterior sclera collagen cross-linking induced by riboflavin-ultraviolet A(UVA)on form-deprived myopia in guinea pigs.METHODES:Twenty-five pigmented guinea pigs of 3-week-old were randomly assigned into 4 groups that included normal control(NOR,n=7),form-deprived(FDM,n=7),normal with riboflavin-UVA cross-linking(NOR+CL,n=5)and form-deprived with cross-linking(FDM+CL,n=6).The NOR+CL group and the FDM+CL group received the riboflavin-UVA induced cross-linking at day 0.FDM was induced by monocularly deprived with facemask in the right eyes.The refraction,axial length and corneal curvature were measured by retinoscopy,A-scan and keratometer respectively in scheduled time points(day 0 and 1,2,3,4 wk after form-deprivation).At the end of 4 weeks’experiment,stress-strain tests of sclera were measured and morphological changes of sclera and retina were examined.RESULTS:After 4 wk,the interocular difference of refractive error were-0.11±0.67,-2.93±0.56,1.10±0.58,and-1.63±0.41 D in the NOR,FDM,NOR+CL,and FDM+CL groups respectively.Mixed-effect linear model revealed significant effect of FDM(P<0.01)and CL(P<0.001).Also,after 4 wk,the interocular difference of axial length were 0.01±0.04,0.29±0.07,-0.13±0.06,and 0.11±0.05 mm in the NOR,FDM,NOR+CL,and FDM+CL group.Mixedeffect linear model revealed significant effect of FDM(P<0.001)and CL(P<0.01).As for corneal curvature,significant interocular difference have not found between any of the two groups.At the end of this experiment,the ultimate stress and elastic modulus were found significantly increased in both CL groups.But no difference was found in the groups without cross-linked.There was no abnormality observed in the retina and RPE cells of the treated eyes.CONCLUSION:The posterior sclera collagen crosslinking induced by riboflavin-UVA can slow down the progress of myopia and increase the sclera biomechanical strength in the guinea pig model of form-deprived myopia.展开更多
AIM：To study the expression of collagen I and transcription factor specificity protein 1（Sp1）,a transforming growth factor-β1（TGF-β1） downstream target,and reveal the impact of the TGF-β1-Sp1 signaling pathway...AIM：To study the expression of collagen I and transcription factor specificity protein 1（Sp1）,a transforming growth factor-β1（TGF-β1） downstream target,and reveal the impact of the TGF-β1-Sp1 signaling pathway on collagen remodeling in myopic sclera.METHODS：Seventy-five 1-week-old guinea pigs were randomly divided into normal control,form deprivation myopia（FDM）,and self-control groups.FDM was induced for different times using coverage with translucent latex balloons and FDM recovery was performed for 1wk after 4wk treatment;then,changes in refractive power and axial length were measured.Immunohistochemistry and reverse transcription-polymerase chain reaction were used to evaluate dynamic changes in collagen I and Sp1 expression in the sclera of guinea pigs with emmetropia and experimental myopia,and the relationship between collagen I and Sp1 levels was analyzed.RESULTS：In the FDM group,the refractive power was gradually changed（from 2.09±0.30 D at week 0 to-1.23±0.69 D,-4.17±0.59 D,-7.07±0.56 D,and-4.30±0.58 D at weeks 2,4,6,and 1wk after 4wk,respectively;P〈0.05）,indicating deepening of myopia.The axial length was increased（from 5.92±0.39 mm at week 0 to 6.62±0.36 mm,7.30±0.34 mm,7.99±0.32 mm,and 7.41±0.36 mm at weeks 2,4,6,and 1wk after 4wk;P〈0.05）.The m RNA and protein expression of Sp1 and collagen I in the sclera of the FDM group was lower than that of the control groups（P〈0.05）,and the reduction was eye-coverage time-dependent.Furthermore,correlation between Sp1 and collagen I down-regulation in the myopic sclera was observed.CONCLUSION：Our data indicate that transcription factor Sp1 may be involved in the regulation of type I collagensynthesis/degradation during myopic sclera remodeling,suggesting that TGF-β1 signaling plays a role in the development and progression of myopia.展开更多
文摘AIM:To study the efficacy difference between formdeprived myopia(FDM)and lens-induced myopia(LIM),the degree of myopia,axial length and pathological changes of the posterior sclera from guinea pigs were evaluated.METHODS:Four-week pigmented guinea pigs were randomly assigned into 3 groups,including normal control(n=6),FDM group with monocular cover(n=11)and LIM group with monocular-7D lens treatment(n=11).FDM group was form-deprived while LIM group was lens-induced for 14d.Refractive error and axial length were measured prior to and post treatment,respectively.Morphological changes of sclera were examined using both light and electronic microscopes.RESULTS:After 14d treatment,refractive errors for FDM group and LIM group were-3.05±0.71D and-2.12±1.29D,respectively,which were significantly more myopic than that of normal controls and fellow control eyes(P【0.01).As for axial length,it was 7.93±0.03 mm for FDM group and 7.89±0.06 mm for LIM group,which were significantly longer than both normal and fellow controls(P【0.01).With respect to both refractory error and axial length,the differences between FDM group and LIM group were not significant(P】0.05).Under light microscope,both FDM group and LIM group showed thinned sclera,disarrangement of fibrosis and enlargeddisassociation between fibers.Consistently,ultrastructural examination showed degenerated fibroblasts and thinned fibers in posterior sclera.CONCLUSION:Following two weeks of myopia induction in guinea pigs,with regard to the degree of myopia,axial length and pathological alterations,there was no significant difference between FDM and LIM models.Therefore,FDM and LIM are equally effective and useful as a model of experimental myopia and guinea pigs are ideal animals for induction of experimental myopia because their high sensitivity to both formdeprivation and lens-induction.
基金Supported by the Tianjin Clinical Key Discipline Project(No.TJLCZDXKQ013)the Research Project of Health Committee in Binhai District,Tianjin(No.2019BWKQ033)。
文摘AIM:To evaluate the effect of posterior sclera collagen cross-linking induced by riboflavin-ultraviolet A(UVA)on form-deprived myopia in guinea pigs.METHODES:Twenty-five pigmented guinea pigs of 3-week-old were randomly assigned into 4 groups that included normal control(NOR,n=7),form-deprived(FDM,n=7),normal with riboflavin-UVA cross-linking(NOR+CL,n=5)and form-deprived with cross-linking(FDM+CL,n=6).The NOR+CL group and the FDM+CL group received the riboflavin-UVA induced cross-linking at day 0.FDM was induced by monocularly deprived with facemask in the right eyes.The refraction,axial length and corneal curvature were measured by retinoscopy,A-scan and keratometer respectively in scheduled time points(day 0 and 1,2,3,4 wk after form-deprivation).At the end of 4 weeks’experiment,stress-strain tests of sclera were measured and morphological changes of sclera and retina were examined.RESULTS:After 4 wk,the interocular difference of refractive error were-0.11±0.67,-2.93±0.56,1.10±0.58,and-1.63±0.41 D in the NOR,FDM,NOR+CL,and FDM+CL groups respectively.Mixed-effect linear model revealed significant effect of FDM(P<0.01)and CL(P<0.001).Also,after 4 wk,the interocular difference of axial length were 0.01±0.04,0.29±0.07,-0.13±0.06,and 0.11±0.05 mm in the NOR,FDM,NOR+CL,and FDM+CL group.Mixedeffect linear model revealed significant effect of FDM(P<0.001)and CL(P<0.01).As for corneal curvature,significant interocular difference have not found between any of the two groups.At the end of this experiment,the ultimate stress and elastic modulus were found significantly increased in both CL groups.But no difference was found in the groups without cross-linked.There was no abnormality observed in the retina and RPE cells of the treated eyes.CONCLUSION:The posterior sclera collagen crosslinking induced by riboflavin-UVA can slow down the progress of myopia and increase the sclera biomechanical strength in the guinea pig model of form-deprived myopia.
基金Supported by the Natural Science Foundation of Anhui Province(No.1508085MH188)Science Foundation of Anhui Provincial Health Bureau(No.13zc040No.13zc046)
文摘AIM：To study the expression of collagen I and transcription factor specificity protein 1（Sp1）,a transforming growth factor-β1（TGF-β1） downstream target,and reveal the impact of the TGF-β1-Sp1 signaling pathway on collagen remodeling in myopic sclera.METHODS：Seventy-five 1-week-old guinea pigs were randomly divided into normal control,form deprivation myopia（FDM）,and self-control groups.FDM was induced for different times using coverage with translucent latex balloons and FDM recovery was performed for 1wk after 4wk treatment;then,changes in refractive power and axial length were measured.Immunohistochemistry and reverse transcription-polymerase chain reaction were used to evaluate dynamic changes in collagen I and Sp1 expression in the sclera of guinea pigs with emmetropia and experimental myopia,and the relationship between collagen I and Sp1 levels was analyzed.RESULTS：In the FDM group,the refractive power was gradually changed（from 2.09±0.30 D at week 0 to-1.23±0.69 D,-4.17±0.59 D,-7.07±0.56 D,and-4.30±0.58 D at weeks 2,4,6,and 1wk after 4wk,respectively;P〈0.05）,indicating deepening of myopia.The axial length was increased（from 5.92±0.39 mm at week 0 to 6.62±0.36 mm,7.30±0.34 mm,7.99±0.32 mm,and 7.41±0.36 mm at weeks 2,4,6,and 1wk after 4wk;P〈0.05）.The m RNA and protein expression of Sp1 and collagen I in the sclera of the FDM group was lower than that of the control groups（P〈0.05）,and the reduction was eye-coverage time-dependent.Furthermore,correlation between Sp1 and collagen I down-regulation in the myopic sclera was observed.CONCLUSION：Our data indicate that transcription factor Sp1 may be involved in the regulation of type I collagensynthesis/degradation during myopic sclera remodeling,suggesting that TGF-β1 signaling plays a role in the development and progression of myopia.
