形觉剥夺下雏鸡后极部巩膜中MMP-2 TIMP-2及RAR β表达变化

Change of MMP-2, TIMP- 2 and RAR β level in chicken posterior sclera with different visual environment

目的分析雏鸡形觉剥夺性近视眼及形觉剥夺性近视恢复眼后极部巩膜中基质金属蛋白酶2（matrix metalloproteinase 2，MMP-2）、组织金属蛋白酶抑制剂2（tissue inhibitor of matrix metalloproteinase 2，TIMP-2）及视黄酸受体-β（retinoic acid receptor—β，RARB）的水平及其相关性。方法选用新孵出家鸡75只，半透明眼罩遮盖的方法对左眼进行形觉剥夺，分为形觉剥夺组，遮盖14d；形觉剥夺恢复组，遮盖11d后，去遮盖3d。右眼为对照眼。取直径8mm的后极部眼组织块，分离出巩膜纤维层和软骨层。RT—PCR检测MMP-2、TIMP-2及RAR β mRNA的相对含量，并将MMP-2、TIMP-2 mRNA水平分别与RARB的mRNA水平作线性相关分析。结果形觉剥夺14d后，纤维层中MMP一2的表达增强（P〈0．01），TIMP一2的表达减弱（P〈0．01）；去剥夺3d后，MMP一2的表达减弱（P〈0．01），而TIMP-2的表达恢复到接近对照眼的水平（P〉0．050软骨层表达没有明显变化。形觉剥夺14d后，RARβ的表达均增强，但纤维层中的表达更为强烈（P〈0．01）。去剥夺3d后，RARB的表达均明显下降（P〈O．01）。MMP一2与RARβmRNA水平呈正相关（P〈0．05，r=0．944）；TIMP-2与RARβmRNA水平呈负相关（P〈O．05，r=-0．863）。结论雏鸡形觉剥夺性近视眼及形觉剥夺性近视恢复眼后极部巩膜纤维层中MMP-2、TIMP-2及RARp的水平均发生明显变化，并有相关性。RARB参与了巩膜纤维层细胞外基质的降解过程。

Objective To analyze the level and relativity of matrix metalloproteinase 2 （MMP-2）, tissue inhibitor of matrix metalloproteinase 2 （TIMP-2） and retinoic acid receptor-~ （RAR^3） of posterior sclera in chicken form-deprivation myopic eyes and form-deprivation myopic recovery eyes.Methods Seven- ty-five newly incubated carnivorous chickens were selected.Their left eyes were covered with semitransparent membrane to deprive form perception, and were divided into 2 trial groups： form-deprived group： coveting for 14 days, and recovery group： covering for 11 days followed by uncovering for 3 days.Posterior ocular tissue of 8ram in diameter was taken.Scleral fiber layer and cartilage layer were isolated.RT-PCR was used to detect the level of MMP-2, TIMP-2 and RARβ .The relativity between the mRNA of MMP-2, TIMP-2 and the mRNA of RARβ were analyzed respectively.Results There was strong expression of MMP-2 and TIMP-2 in fibrous sclera, while there was very weak expression in cartilage sclera.There were no obvious changes in the cartilage sclera in form-deprivation and recovery from form-deprivation.While in the fibrous sclera, MMP-2 was in- creased （P〈0.01）, TIMP-2 was decreased （P〈0.01） at 14 days of form-deprivation.At 3 days recovery from form-deprivation, MMP-2 was decreased （P〈0.01）, TIMP-2 was increased （P〈0.05）.At 14 days of form-deprivation, RARβ increased in the sclera.It increased more obvious in the fibrous sclera （P〈0.01）.At 3 days recovery from form-deprivation, RARβ decreased.The relative content of mRNA of MMP-2 was positive correlation with that of RARβ （P〈0.05, r=0.944）.The relative content ofmRNA of TIMP-2 was negative correlation with that ofRAR[3 （P〈0.05, r=0.863 ）.Conclusions During form-deprivation and form-deprivation recovery, MMP-2, TIMP-2 and RARβ contents in posterior fibrous sclera change significantly. RARβ takes part in the degeneration process of fibrous scleral extra cellular matrix.