不同浓度阿托品滴眼液对豚鼠形觉剥夺性近视的影响

目的探讨不同浓度阿托品滴眼液对单眼形觉剥夺幼年豚鼠的屈光发育的影响，并分析阿托品抑制近视的可能作用位点和机制。方法实验研究。将80只3周龄体质量在100 g左右的豚鼠随机分至5组：单眼形觉剥夺4周组（8只）、形觉剥夺加点药同时进行4周组（每个浓度各8只）、形觉剥夺2周后再加点药2周组（每个浓度各8只）、单纯点药4周组（每个浓度各6只）、空白对照组（6只）。阿托品粉剂溶于单蒸水配制成3个浓度的阿托品滴眼液：0.2%、1.0%、3.0%。每天早上8∶30-9∶00间点药。在实验前、实验2 周、实验4 周时测量各组豚鼠屈光力、角膜曲率、眼轴长度等相关生物学参数。实验4周结束后取豚鼠眼视网膜做冰冻切片，免疫荧光法标记豚鼠视网膜上表达胰高血糖素的细胞。采用配对样本t检验和重复测量的双因素方差分析进行数据分析。结果单纯形觉剥夺组，实验2周后实验眼屈光度较自身对照眼往近视方向发展，同时伴有玻璃体腔加深、眼轴延长，差异有统计学意义（t=-11.09、7.89、3.73，P<0.05）；4周后，差异更显著。形觉剥夺加点药同时进行的3个浓度组，实验2周后实验眼与自身对照眼的各屈光参数差异均无统计学意义，而2眼差值与单纯剥夺组比较，屈光度、玻璃体腔深度、眼轴长度差异均有统计学意义（F=26.335、6.479、6.910，P<0.05）；4周后，3个浓度组实验眼屈光度与自身对照眼比较均开始往近视方向发展，差异有统计学意义（t=-4.67、-7.54、-2.78，P<0.05），同时玻璃体腔加深，眼轴延长，而2眼差值与单纯剥夺组比较，各屈光参数的差异仍有统计学意义（F=16.962、5.193、6.882，P<0.05）；但3个浓度组的组间两两比较显示，各参数实验前后差异无统计学意义。形觉剥夺2周后再加点药2周组，实验4周后各浓度组2眼差值与单纯剥夺4周组比较，各屈光参数差异均无统计学意义。各组豚鼠视网膜上均未标记出胰高血糖素表达阳性的细胞。结论在3%的浓度范围内，阿托品滴眼液能通过抑制玻璃体腔加深、眼轴延长从而部分抑制豚鼠形觉剥夺性近视的发生，且作用效果没有明显的浓度依赖性。但在近视形成后运用阿托品，并不能抑制近视的进展。胰高血糖素能途径没有参与阿托品对豚鼠近视发生发展的作用过程。

Effects of different concentrations of atropine eye drops on guinea pigs with form-deprivation myopia

ObjectiveTo study the effects of different concentrations of atropine eye drops on guinea pigs with form-deprivation myopia； to analyze the potential mechanisms of atropine. MethodsIn this experimental study， 80 3-week-old guinea pigs weighing approximately 100 g were randomly assigned to 5 groups： 4 weeks of monocular form deprivation （n=8）， 4 weeks of form deprivation and atropine （n=8 for each concentration subgroup）， 4 weeks of form deprivation and 2 weeks of atropine （n=8 for each concentration subgroup）， 4 weeks of atropine （n=6 for each concentration subgroup）， and a control group（n=6）. Pure atropine powder was dissolved in distilled water to create three different concentrations of atropine solution： 0.2%， 1.0%， 3.0%. The atropine eye drops were applied once every morning at 8∶30-9∶00. All the groups underwent biometric measurements （refraction， corneal curvature， axial length， etc.） at three timepoints： prior to the experiment， 2 weeks into the experiment， and at the end of the experiment. Immunofluorescence was used to mark the guinea pig retinal cells that had a positive expression of glucagon. The results were analyzed with a paired-sample t test and two-way repeated measures ANOVA. ResultsAfter 2 weeks of form deprivation in the monocular form-deprived group， the experimental eyes developed myopia with a deepening of the vitreous chamber and an elongation of the ocular axis compared to the contralateral eyes. The difference was statistically significant （t=-11.09， 7.89， 3.73， P<0.05）. Four weeks later， the experimental eyes had an even greater myopic shift. In the group with 4 weeks of form deprivation and atropine， there were no significant differences after 2 weeks when changes in refraction， vitreous chamber depth and axial length were compared between the experimental eyes and contralateral eyes of all three subgroups. Furthermore， there were no statistically significant differences between the contralateral and experimental eyes in each subgroup compared to the monocular form-deprived group （F=26.335， 6.479， 6.910， P<0.05）. After 4 weeks， in the group with 4 weeks of form deprivation and atropine， the experimental eyes in all three subgroups began to develop myopia compared to the contralateral eyes （t=-4.67， -7.54， -2.78， P<0.05）. Meanwhile， the vitreous chamber was deepening and the axis was elongating， but there were still statistically significant differences between the contralateral and experimental eyes of each subgroup compared to the monocular form-deprivation group （F=16.962， 5.193， 6.882， P<0.05）. However， there were no significant differences for any refractive parameter among all three subgroups. There was no statistically significant difference for any refractive parameter when the experimental/contralteral eyes of each subgroup in the group with 2 weeks of form deprivation plus 2 weeks of atropine were compared to the group with 4 weeks of form deprivation. None of the guinea pig retinal cells in any group were marked to have a positive expression of glucagon. ConclusionThe 3% concentration atropine eye drops can partly inhibit form-deprivation myopia by preventing the deepening of the vitreous chamber and elongation of the ocular axis in guinea pigs， and the effect of atropine does not show a concentration-dependent pattern. The use of atropine during the latter stage of form deprivation cannot limit the progress of myopia. Glucagon is not involved in the effect of atropine on the development of form-deprivation myopia in guinea pigs.