实验性外斜视猫模型内直肌的NGF和Myf5表达变化

Changes in NGF and Myf5 expression in extraocular muscles of a cat model with exotropia

目的 观察共同性外斜视猫模型内直肌中神经生长因子（NGF）和生肌调节因子5（Myf5）表达变化及其与斜视时间的相关性.方法 实验研究.选择处于视觉发育敏感期内幼猫（4～6周）18只,随机分为实验组和对照组;根据斜视时间实验组分为斜视1个月组、2个月组、3个月组,每组各3只;对照组随机分为对照1、2、3组（分别与斜视1个月、2个月、3个月组对应）,每组各3只.实验组通过右眼外直肌缩短联合前徙制作外斜视模型,分别于术后1个月、2个月、3个月取实验组及相应对照组的右眼内直肌,固定、脱水、石蜡包埋、切片,免疫组织化学染色法检测内直肌NGF和Myf5平均光密度值,所得数据用小样本成组资料的t检验或t＆#39;检验、重复测量的方差分析及Pearson相关分析法进行统计.结果 ①实验组内直肌中NGF的平均光密度值低,斜视2个月组、3个月组与对应对照组内直肌中NGF的表达量进行比较,差异具有统计学意义（t=7.678、15.532,P＜0.01）.②Myf5在实验组内直肌中的平均光密度值低,斜视2个月组、3个月组与其对照组内直肌Myf5的表达量差异具有统计学意义（t=5.819、7.029,P＜0.01）.③外斜视猫模型内直肌中NGF、Myf5平均光密度值与斜视时间呈负相关（r=-0.984、-0.971,P＜0.05）.结论 ①外科手术的方法可成功制作外斜视猫模型.②实验性外斜视猫内直肌中NGF和Myf5表达量的降低可能参与了斜视的发生.③实验性外斜视猫内直肌中NGF和Myf5的表达量随斜视病程的延长而降低,该变化可能与斜视病情的进展相关.

Objective To observe the changes in the expression of nerve growth factor （NGF） and myocyte differentiation factor 5（Myf5） in the medial rectus muscle of a cat model with strabismus.Methods Eighteen cats that were in the 4-6 weeks sensitive period were selected for surgery to create an exotropia model.All animals were randomly divided into experimental and control groups.Medial rectus muscles from both the experimental and control groups were collected at 1 month,2 months,and 3 months after strabismus surgery.These samples were prepared for histologic examination by fixation,paraffin embedding and slicing.Immunohistochemistry staining was used to detect NGF and Myf5 expression and an optical density analysis was used to measure the average optical density.Data were analyzed using t test or t＆#39; test,repeat measured ANOVA and Pearson correlation test.Results ①There were significant differences in NGF expression in the medial rectus muscles of the experimental and control groups between 2 and 3 months （t=7.678,15.532,P〈0.01）.②There were also significant differences in the expression of Myf5 in the medial rectus muscles of the experimental and control groups between 2 and 3 months （t=5.819,7.029,P〈0.01）.③There was a negative relationship between NGF and Myf5 expression and the development of strabismus （r=-0.984,--0.971,P〈0.05）.Conclusion ①he surgical method can successfully produce a concomitant exotropia cat model.②The reduced expression of NGF and Myf5 in the medial rectus muscle in the experimental strabismus cat model may be involved in the occurrence of strabismus.③NGF and Myf5 expression in the medial rectus muscle are reduced with the duration of the extension,which may be related to the progress of a strabismus condition.