Objective To investigate the changes in refraction and ocular biometric parameters in monocular form-deprivation myopia, and to investigate whether myopia development is associated with changes in the retinal levels of Pax6 messenger RNA (mRNA) and the DNA methylation state in cytosine-phosphate-guanine (CpG) sites in the Pax6 promoter. Methods Experimental study. A diffuser lens was worn over one eye of one group of C57BL/6 mice for 4 weeks to establish a monocular form deprivation (MD) myopia model, and another group wore a diffuser lens for 4 weeks, then the goggles were removed for 1 week to build a recovery model. A total of 36 C57BL/6 mice (postnatal day 21) were randomly assigned to the MD group (n=12), a normal control (NC) group (n=12); and MD recovery group (n=6), a corresponding control group (n=6). Ocular biometry was determined in mice by an EIR (eccentric infrared photorefractor) and OCT (optical coherence tomography). The Pax6 mRNA level in the retina was determined by real-time PCR, and the Pax6 methylation state was observed by bisulfite DNA sequencing. Data were analyzed using paired t test or independent t test. Results After 4 weeks of form deprivation, a significant myopic shift had been induced in the treated eyes (MD-T) (-3.27±0.52 D) compared to the contralateral eyes (MD-C) (1.13±1.17 D) (t=-12.726, P<0.01) and normal control eyes (NC) (1.65±1.69 D) (t=-6.832, P<0.01). Pax6 mRNA in the MD-T eyes (0.495±0.247) decreased significantly compared to the MD-C eyes (1.011±0.477) (t=-3.16, P<0.05) and the NC eyes (1.071±0.401) (t=-2.99, P<0.05). One week after the removal of the diffuser lenses, Pax6 mRNA expression in recovery eyes had been fully restored to levels in the control eyes. The methylation percentage in CpG sites of the Pax6 promoter in the MD-T eyes was not significantly different compared to MD-C and NC eyes. Conclusion Monocular form deprivation myopia can be induced in C57BL/6 mice. Retinal Pax6 mRNA was reduced in the MD-T eyes compared to MD-C and NC eyes, but the changes in Pax6 mRNA may not be caused by DNA methylation of the CpG island in the promoter region of Pax6.
王晓静,陈阿银,刘懋,赵福新,黄芙蓉,周翔天. C57BL/6小鼠形觉剥夺性近视视网膜Pax6的表达及其启动子区域CpG岛甲基化的改变[J]. 中华眼视光学与视觉科学杂志, 2015, 17(6): 326-330.
Wang Xiaojing,Chen Ayin,Liu Mao,Zhao Fuxin,Huang Furong,Zhou Xiangtian. Study on mRNA expression and DNA methylation of Pax6 in form-deprived myopia in C57BL/6 mice. Chinese Journal of Optometry Ophthalmology and Visual science, 2015, 17(6): 326-330. DOI: 10.3760/cma.j.issn.1674-845X.2015.06.003
Vitale S, Ellwein L, Cotch MF, et al. Prevalence of refractive error in the United States, 1999-2004[J]. Arch Ophthalmol,2008,126(8):1111-1119.
[2]
Wojciechowski R. Nature and nurture: the complex genetics of myopia and refractive error[J]. Clin Genet,2011,79(4):301-320.
[3]
Goldschmidt E, Jacobsen N. Genetic and environmental effects on myopia development and progression[J]. Eye (Lond),2014, 28(2):126-133.
[4]
Duncan EJ, Gluckman PD, Dearden PK. Epigenetics, plasticity, and evolution: How do we link epigenetic change to phenotype?[J]. J Exp Zool B Mol Dev Evol,2014,322(4):208-220.
[5]
Zhou X, Ji F, An J, et al. Experimental murine myopia induces collagen type Ialpha1 (COL1A1) DNA methylation and altered COL1A1 messenger RNA expression in sclera[J]. Mol Vis,2012, 18:1312-1324.
[6]
He Y, Pan Z, Luo F. A novel PAX6 mutation in Chinese patients with severe congenital aniridia[J]. Curr Eye Res,2012, 37(10):879-883.
[7]
Sonoda S, Isashiki Y, Tabata Y, et al. A novel PAX6 gene mutation (P118R) in a family with congenital nystagmus associated with a variant form of aniridia[J]. Graefes Arch Clin Exp Ophthalmol,2000,238(7):552-558.
[8]
Hammond CJ, Andrew T, Mak YT, et al. A susceptibility locus for myopia in the normal population is linked to the PAX6 gene region on chromosome 11: a genomewide scan of dizygotic twins[J]. Am J Hum Genet,2004,75(2):294-304.
[9]
Liang CL, Hsi E, Chen KC, et al. A functional polymorphism at 3′UTR of the PAX6 gene may confer risk for extreme myopia in the Chinese[J]. Invest Ophthalmol Vis Sci,2011,52(6):3500-3505.
[10]
Han W, Leung KH, Fung WY, et al. Association of PAX6 polymorphisms with high myopia in Han Chinese nuclear families[J]. Invest Ophthalmol Vis Sci,2009,50(1):47-56.
[11]
Simpson CL, Hysi P, Bhattacharya SS, et al. The Roles of PAX6 and SOX2 in myopia: Lessons from the 1958 British Birth Cohort[J]. Invest Ophthalmol Vis Sci,2007,48(10):4421-4425.
[12]
Bhat SP, Rayner SA, Chau SC, et al. Pax-6 expression in posthatch chick retina during and recovery from form-deprivation myopia[J]. Dev Neurosci,2004,26(5-6):328-335.
[13]
Zhong XW, Ge J, Deng WG, et al. Expression of pax-6 in rhesus monkey of optical defocus induced myopia and form deprivation myopia[J]. Chin Med J (Engl),2004,117(5):722-726.
[14]
Schaeffel F, Burkhardt E, Howland HC, et al. Measurement of refractive state and deprivation myopia in two strains of mice[J]. Optom Vis Sci,2004,81(2):99-110.
[15]
Zhou X, Xie J, Shen M, et al. Biometric measurement of the mouse eye using optical coherence tomography with focal plane advancement[J]. Vision Res,2008,48(9):1137-1143.
[16]
Wallman J, Winawer J. Homeostasis of eye growth and the question of myopia[J]. Neuron,2004,43(4):447-468.
[17]
Ton CC, Hirvonen H, Miwa H, et al. Positional cloning and characterization of a paired box- and homeobox-containinggene from the aniridia region[J]. Cell,1991,67(6):1059-1074.
[18]
Rath MF, Bailey MJ, Kim JS, et al. Developmental and daily expression of the Pax4 and Pax6 homeobox genes in the rat retina: localization of Pax4 in photoreceptor cells[J]. J Neurochem,2009,108(1):285-294.
[19]
Stanescu D, Iseli HP, Schwerdtfeger K, et al. Continuous expression of the homeobox gene Pax6 in the ageing human retina[J]. Eye (Lond),2007,21(1):90-93.
[20]
Morgan IG, Ashby RS, Nickla DL. Form deprivation and lens-induced myopia:are they different?[J]. Ophthalmic Physiol Opt,2013,33(3):355-361.
[21]
Barathi VA, Boopathi VG, Yap EP, et al. Two models of experimental myopia in the mouse[J]. Vision Res,2008,48(7):904-916.