中文摘要：

目的：检测MMP-9基因敲除小鼠（MMP-9-（-/-））和野生型小鼠磨牙牙胚中釉原蛋白和成釉蛋白的表达。方法：使用免疫组化方法检测出生后2d（P2）、5d（P5）、7d（P7）野生型小鼠和MMP-9-（-/-）小鼠下颌磨牙牙胚中釉原蛋白和成釉蛋白的表达分布。结果：在P2时,釉原蛋白主要表达在成熟的成釉细胞胞、及其相邻的成牙本质细胞内,敲除MMP-9后,釉原蛋白的表达可扩散至牙乳头间充质;在P5和P7时,釉原蛋白的表达分布在野生型小鼠和MMP-9-（-/-）小鼠中无差异,但在MMP-9-（-/-）小鼠中釉原蛋白在成釉细胞中的表达量明显增强。在P2、P5和P7时,成釉蛋白的表达分布和表达量在野生型小鼠和MMP-9-（-/-）小鼠中均无差异。结论：MMP-9可能通过酶切釉原蛋白而影响其表达分布。

英文摘要：

Objective：To detect the expressions of Amelogenin and Ameloblastin in wild-type mice and MMP-9gene knock-out mice（MMP-9-（-/-））.Methods：The expression levels of Amelogenin and Ameloblastin in tooth germs were detected with immunohistochemistry in wild-type and MMP-9-（-/-）mice at post-natal day 2（P2）,5（P5）,and 7（P7）.Results：At P2,Amelogenin was mainly expressed in matured ameloblasts and the underlying odontoblasts.However,in MMP-9-（-/-）mice,the expression of amelogenin was expanded to the dental mesenchyme.No difference was found in the expression pattern of Amelogenin between wild-type mice and MMP-9-（-/-）mice at P5 and P7.However,the expression level of Amelogenin in ameloblasts was highly increased in MMP-9-（-/-）mice compared with that in wild-type mice.No obvious differences were detected in the expression pattern or expression level of Ameloblastin between wild-type mice and MMP-9-（-/-）mice at P2,P5,and P7.Conclusion：MMP-9might be able to degrade Amelogenin,and further influence the expression pattern of Amelogenin.