负透镜诱导豚鼠离焦性近视眼后部巩膜Ⅰ型胶原、基质金属蛋白酶-2及金属蛋白酶组织抑制因子-2的表达

目的 观察负透镜诱导豚鼠离焦性近视发生时眼后部巩膜Ⅰ型胶原、基质金属蛋白酶2(MMP-2)和金属蛋白酶组织抑制因子-2(TIMP-2)表达的变化.方法 将30只新生有色豚鼠随机分为透镜诱导组(单眼-10D透镜诱导,n=20)和正常对照组(无处理组,n=10),4周后测量屈光度,眼球冰冻切片行后部巩膜Ⅰ型胶原免疫组织化学染色,Western blot检测眼后部巩膜MMP-2和TIMP-2蛋白表达.结果负透镜诱导4周后,透镜诱导组豚鼠诱导眼后部巩膜Ⅰ型胶原密度和TIMP-2蛋白表达明显低于对侧眼(P均<0.01),MMP-2蛋白表达明显高于对侧眼(P<0.01);但透镜诱导组对侧眼上述指标与正常对照组双眼相比差异均无统计学意义(P均>0.05).透镜诱导组诱导眼屈光度与眼后部巩膜Ⅰ型胶原(r=0.79,P<0.01)表达和TIMP-2表达量(r=0.74,P<0.05)呈显著正相关,与MMP-2表达量呈显著负相关性(r=-0.78,P<0.01).结论 离焦性近视发生过程中可能存在MMP-2参与的眼后部巩膜细胞外基质改变.

Expressions of Collagen I,Matrix Metalloproeinases-2,and Tissue Inhibitor of Matrix Metalloproteinase-2 in the Posterior Sclera of Newborn Guinea Pigs with Negative Lens-defocused Myopia

Objective To observe the expressions of the collagen Ⅰ,matrix metalloproeinages-2(MMP-2),and tissue inhibitor of matrix metalloproteinase-2(TIMP-2)in the posterior selera of newborn guinea pigs with negative lens-defocused myopia.Methods Newborn guinea pigs were monocularly defocused by-10D lens.After 4 weeks of defocus,the eyes were removed to provide posterior scleral samples for detection.Expression of collagen Ⅰ was detected by immunohistochemistry on frozen sections of guinea pig sclera,and the protein levels of MMP-2 and TIMP-2 were evaluated by Western blot.Results Immunohistochemical analysis indicated that the expressions of collagen Ⅰ and TIMP-2 were significantly lower and the expression of MMP-2 wag significantly higher in the posterior selera in the defocused eyes than in the contralateral eyes(all P<0.01).However,all these indicators were not significantly different between the contralateral eyes and normal control eyes(all P > 0.05).In the defocused animals,the refraction of defocused eyes was positively correlated with the expression levels of collagen Ⅰ(r = 0.79,P < 0.01)and TIMP-2(r = 0.74,P < 0.05)and was negatively correlated with the expression level of MMP-2(r =-0.78,P < 0.01)in posterior sclera.Conclusion Alteration of extracellular matrix in the posterior sclera,probably participated by MMP-2,may exist during the development of defocus-induced myopia.