C57BL／6小鼠形觉剥夺性近视动物模型的建立

Form deprivation myopia in C57BL/6 mice

目的探讨C57BL／6小鼠形觉剥夺性近视与眼球生物学参数的变化，揭示小鼠实验性近视形成的敏感期，以及形觉剥夺对小鼠屈光发育的影响。方法实验研究。23日龄C57BL／6小鼠74只，随机分为3组，单眼形觉剥夺组：剥夺2周（n=12）、3周（n=20）和4周（n=18），对侧眼作为自身对照；形觉剥夺恢复组（n=10）：单眼形觉剥夺4周，分别恢复4d和7d；正常对照组（n=14）。实验前后分别用红外偏心摄影验光仪测量小鼠眼球的屈光状态，修正过的人眼角膜曲率计测量角膜曲率半径，相干光断层扫描仪测量眼球生物学参数，包括眼前节、晶状体厚度、玻璃体腔深度和眼轴长度等。对组内实验眼和对侧眼的屈光力、角膜曲率半径、眼球参数的比较采用配对t检验，不同组间比较采用独立样本t检验进行统计学分析。结果形觉剥夺2周，实验眼相比对侧眼向近视方向漂移（-0．85±1．65）D，眼球各生物学参数未见明显改变；形觉剥夺3周，实验眼相比对照眼向近视方向漂移（-4．27±1．60）D（t=-1．72，P=0．095）；形觉剥夺4周组，实验眼相比对侧眼向近视方向漂移（-5．27±1．28）D（t=-2．64，P〈0．05）并伴玻璃体腔深度延长（27±13）μm和眼轴长度增加（28±12）μm；去除眼罩7d，实验性近视完全恢复。结论小鼠单眼形觉剥夺4周可诱导出相对近视，但诱导时间较其他近视动物模型长；去除眼罩7d，实验性近视完全恢复；利用相干光断层扫描仪测量小鼠眼球生物学参数可以较好反映屈光度的改变。

Objective To investigate the changes of refraction and ocular biometric parameters in form deprived myopia, and try to find the effective duration to induce significant myopic shift in C57BL/6 mice. Methods It was an experimental study. Seventy-four C57BL/6 mice, approximately 23 days old, were divided into three groups randomly： FD （Form-deprivation） , Recovery and Normal control groups. FD group was treated with diffuser worn on one eye for 2 weeks （ n = 12）, 3 weeks （ n = 20） and 4 weeks （ n = 18）, respectively. In Recovery group, diffusers were removed after 4 weeks form deprivation, and vertical meridian refraction and other biometric parameters were performed immediately on 4^th and 7^th day. The same measurements were performed in the normal control group at the same time-points. Refraction was measured by photoretinoscopy and corneal radius of curvature （CRC） was measured by a modified keratometery. Corneal thickness （CT）, anterior chamber depth （ACD）, lens thickness （LT）, vitreous chamber depth （VCD）, and axial length （AL） were measured by optical coherence tomography （OCT） with focal plane advancement. Results The FD eyes were approximately -0. 85 D more myopic compared to the fellow and the normal control eyes after 2 weeks form deprivation （P 〉 0. 05 ）. After 3 weeks form deprivation, treated eye had a obvious myopic shift （about -4. 27 D） compared to fellow eye, with increased vitreous chamber depth and axial length, however, there was no statistic difference among FD eye, fellow eye and control eye. And after 4 weeks form deprivation, treated eyes were induced significant myopic shift （about -5.22 D） compared with the fellow eye. The difference in refraction of form-deprived and fellow eyes was significantly correlated with the difference in vitreous chamber depth and axial length, which indicate that the induced myopia was mainly axial. The relative myopia shifted rapidly diminished in 4 days after removing the diffuser, followed by a slower recovery. A complete refraction recovery occurred by 7 days after removal of the diffuser compared to the fellow and normal control eyes （ P 〉 0. 05 ）. Conclusion Form deprivation myopia can be induced in C57BL/6 mice, but it required longer period than other animals; A complete recovery occurred by 7 days after removal of the diffuser. Optical Coherence Tomography is a useful instrument to measure mouse eye dimension.