豚鼠离焦性近视眼模型组织形态学观察及短期恢复对屈光和眼轴的影响

THE OBSERVATION OF SCLERA MORPHOLOGICAL CHANGES THE DEFOCUS MYOPIA MODEL OF GUINEA PIG AND THE EFFECTS ON REFRACTIVE STATUS AND AXIAL LENGTH AFTER VISION ENVIRONMENT CHANGE

目的:建立凹透镜诱导的豚鼠离焦性近视眼模型,观察视环境的改变即离焦与近视形成后的短期恢复对豚鼠屈光状态、眼轴长度的影响,以及巩膜组织形态学改变。方法:-7D的凹透镜离焦14d天建立豚鼠光学离焦性近视眼模型,检测屈光度和眼轴长度变化,光镜和电镜进行巩膜胶原纤维形态学观察,苦味酸特殊染色进行巩膜胶原半定量。结果:实验眼的后极部巩膜变薄,胶原纤维排列紊乱,间隙变大,小直经纤维增多以及成纤维细胞的形态异常,离焦诱导近视眼形成后去除镜片、经过2d的恢复,近视度数下降,进一步证实短期视环境改变即可引起屈光度变化,但眼轴长度没有改变。巩膜形态学观察见离焦性近视眼豚鼠后部巩膜胶原纤维排列紊乱,巩膜变薄。电镜下胶原纤维密度减少,小直径胶原纤维增多,成纤维细胞形态不规则。苦味酸-天狼猩红胶原染色显示I型胶原主要分布于后极部,实验眼I型胶原纤维密度减少,排列紊乱。结论:实验性近视眼的形成是巩膜异常重塑的过程,Ⅰ型胶原的改变是近视眼巩膜重塑的重要因素,但是巩膜重塑导致的眼轴伸长短期内不能恢复。

Objective：To establish the concave lens induced defocus myopia model of guinea pig, observe the vision environment change, and the effects on refractive status and axial length of guinea pigs from the short term of recovery after defocus and myopia, as well as the sclera morphological changes. Methods：After 14 days optical defocus by means of -7D concave lens, and observe the change on refractive status and axial length of all groups, the posterior sclera collagen fiber arrangement observed by morphological ob- servation and electron microscope , Picric acid - Sirius Red collagen staining showed I type collagens. Results：After 14 days optical defocus by means of -7D concave lens, it can result in myopia of guinea pig , after the lens is removed. After two days of recovery, the degree of myopia is decreased, which further confirm that the the diopter and the axial length differences between groups and in groups have no statistic significance （ P 〉 0. 05 ）. The morphological observation of sclera found that the posterior sclera collagen fiber arrangement of guinea pigs with defocus myopia is out of order and the sclera gets thinner. The density of the collagen fibers under elec- tron microscope is decreased and the small - diameter collagen fibers are increased and the fibroblasts cells are irregular. Picric acid - Sirius Red collagen staining showed that I type collagens are mainly distributed in the posterior pole and the density of I type collagenfibers of the experimental eyes is reduced and the arrangement is disordered. Conclusion：The guinea pigs may be successfully induced to defocus with -7D concave lens for 14 -day and the sclera of the posterior pole .of the experimental eye becomes thinning and the collagen fiber arrangement is disordered. Short - term environmental change can cause the diopter change, but the axial length is not changed, the axial elongation caused by sclera remodeling can not be restored within short - term. I type collagen in sclera of guinea pig mainly is located at the posterior part, the change of I type collagen is an important factor in myopia scleral remodeling.