AGE-DEPENDENT CHNGES OF MOLECULR INTERACTION IN PERIODONTAL TISSUEU.

我们以前研究了小鼠牙周组织中BrdU和TUNEL阳性细胞的年龄依赖性变化，并表明与衰老相关的细胞成分的显着减少发生在粘膜下结缔组织中引起的细胞凋亡。在此基础上，我们还研究了小鼠各器官组织的细胞动力学随衰老的变化。BrdU阳性细胞在生后30周及以后各年龄组的牙龈、颊粘膜、皮肤和毛囊上皮层均明显减少。生后20周及以后各年龄组牙龈黏膜下组织、颌下腺粘液腺泡细胞和浆液腺泡细胞TUNEL阳性细胞数均增多。衰老标志蛋白-30（Senecent marker protein-30，SMP-30）是一种与年龄相关的标志蛋白，在脑和肝中表达。已知SMP-30与细胞中的抗肿瘤活性相关。采用RT-PCR方法检测SMP-30在生后15周小鼠牙龈组织中的表达。进一步对10周和15周鼠牙龈组织进行cDNA差减，发现10周鼠牙龈组织中有68个基因差异表达，15周鼠牙龈组织中有51个基因差异表达。SMP-30与这些差异表达基因的分子相互作用正在进行中。

We previously examined the age-dependent change of BrdU- and TUNEL-positive cells in the mouse periodontal tissue, and showed that a significant decrease of cellular component in association with aging occurred in the submucosal connective tissue caused by apoptosis. Based on this result, we also examined the cell kinetic change of various organs and tissues in mouse with aging. Decrease of BrdU-positive cells was observed in the epithelial layer of gingiva, buccal mucosa, skin and hair follicle at 30 weeks and following ages after birth. Meanwhile, increase of TUNEL-positive cell was demonstrated gingival submucosal tissue, and mucinous and serous acinar cells of submandibular gland at 20 weeks and following ages after birth. Thus age dependent change of the cell kinetic is evident in the gingival tissue, and is therefore seemed to be related with gingival recession.Senecent marker protein-30(SMP-30) is age-related marker protein, and is known to be expressed in brain and liver. SMP-30 is known to be related the apoptosis-resistant activity in cells. We examined the expression of SMP-30 in the mouse gingival tissue at 15 weeks after birth by RT-PCR. Furthernmore, we performed cDNA subtraction between 10 and 15 weeks aged mouse gingival tissue, and found that 68 genes in the 10 weeks, and 51 genes in the 15 weeks, were differentially expressed. Molecular interaction of SMP-30 and these differentially expressed genes are now proceeding.