Expression and role of specificity protein 1 in the sclera remodeling of experimental myopia in guinea pigs

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.

Dynamic changes of activator protein 1 and collagen I expression in the sclera of myopia guinea pigs

AIM: To investigate the dynamic changes of activator protein 1(AP1) and collagen I expression in the sclera of form-deprivation myopic model in guinea pigs. METHODS: A form-deprivation myopic model in guinea pigs were established with the left eye covered for 2 to 6 wk(FDM group). Normal control group(n=25) were untreated. Changes in refractive power and axial length(AL) were measured and recorded at different time points. Expressions of AP1 and collagen 1 of the sclera were measured with Western blotting and reverse transcription-polymerase chain reaction(RT-PCR). The relationship between AP1 and collagen I levels was analyzed. RESULTS: After 0, 2, 4, 6 wk, and 4/-1 wk of form-deprivation, the diopter in the FDM group was gradually changed(2.08±0.31,-1.23±0.68,-4.17±0.58,-7.07±0.55, and-2.67±0.59 D, respectively, P<0.05), and the AL was gradually increased(5.90±0.38, 6.62±0.37, 7.30±0.35, 7.99±0.31, and 6.97±0.32 mm, respectively, P<0.05). With the prolongation of covered time, the protein expressions of AP1 and collagen I in the FDM group were gradually down-regulated(all P<0.05);the mRNA expressions of them were also gradually down-regulated(all P<0.05);and there was positive correlation between them. The control group had no obvious change in each index(all P>0.05). CONCLUSION: AP1 may be an important transcription factor involved in the regulation of collagen I synthesis and degradation during myopic scleral remodeling.

Effects of scleral encircling surgery on vitreous cavity length and diopter

AIM： To observe the changes of vitreous cavity length and diopter after scleral encircling（SE） produce.·METHODS： This prospective study included 68 eyes of68 non-consecutive patients with macula-off retinal detachment who were operated by SE surgery. The corneal refractive power, ocular axial length and diopter were measured by keratometer, A-mode ultrasonic meter and computed dioptometer.· RESULTS： There was no significant difference in corneal refractive power among preoperative and post operative 1, 3 and 6mo（0.57±0.54 D at pre-surgery; 0.72±0.26 D at 1mo; 0.71 ±0.34 D at 3mo; 0.69 ±0.31 D at 6mo;all P 〉0.05）. Axial lengths were obviously lengthened,especially in vitreous cavity length（17.87 ±3.09 mm,19.69 ±3.12 mm, 18.97 ±3.56 mm, 18.76 ±3.47 mm, 18.68 ±3.42 mm at pre-surgery, 1wk, 1, 3 and 6mo postoperatively,P 〈0.05） and diopter also increased at beginning and then recovered gradually. After 1 and 3 mo, axial length（vitreous cavity length） and myopia were more and in higher degree than before surgery.·CONCLUSION： The change of postoperative vitreous cavity length is the main factor that results in the changes of axial length and then makes the change of diopter.

The association of LOXL1 polymorphisms with exfoliation syndrome/glaucoma: Meta-analysis

AIM: To investigate the association of lysyl oxidaselike 1(LOXL1) single nucleotide polymorphisms(SNPs)with exfoliation syndrome(XFS)/exfoliation glaucoma(XFG).METHODS: Published manuscripts from Pub Med and EMBASE were identified until May 2014. Summary odds ratios(ORs) and 95% confidence intervals(CIs) for LOXL1(rs1048661, rs2165241 and rs3825942) polymorphisms and the risk of XFS/XFG were estimated using random-or fixed- effect model.· RESULTS: The three LOXL1 polymorphisms(rs1048661, rs3825942, and rs2165241) were associated with an increased risk for XFS/XFG among Caucasians,with OR 2.19(1.96-2.45), 8.8(6.05-12.79) and 3.41(3.11-3.73), respectively. On the contrast, the rs1048661 and rs2165241, but not rs3825942 polymorphism, have a potential protective effect on XFS/XFG in Asians, with OR0.06(0.02-0.18), 0.15(0.09-0.25), respectively.CONCLUSION: There is strong evidence that LOXL1 polymorphisms are associated with XFS/XFG risk. The strength of risk might be ethnicity-dependent.