School of Dental Medicine, University of Split, Šoltanska 2, 21000 Split, Croatia.
Arch Oral Biol. 2010 Dec;55(12):1007-16. doi: 10.1016/j.archoralbio.2010.07.024. Epub 2010 Aug 22.
To investigate the spatial and temporal expression of proliferation Ki-67 marker, pro-apoptotic Bax and anti-apoptotic Bcl-2 proteins during early development of the human tooth.
Histological sections of eight human conceptuses, 5-10 postovulatory weeks old, were used for immunolocalization for Ki-67, Bax and Bcl-2 markers. Quantification was performed by calculating the fraction of Ki-67 positive cells, expressed as a mean ± SD, and analysed by Mann-Whitney test, Kruskal-Wallis and Dunn's post hoc test.
In 6th-7th developmental weeks, the tooth germ and dental crest contained 37% of proliferating cells, which increased to 40% in the 8th week, and then decreased to 15% in the 10th week, whilst the proliferation in the ectomesenchyme subsequently dropped from 37% to 23%. Epithelial parts of the enamel organ displayed similar proliferation activity (31-36%), dental crest 10%, whilst enamel knot showed no proliferating activity. The tooth ectomesenchyme contained more proliferating cells (50%) than the jaw ectomesenchyme (35%), and both dropped to 28% in the 10th week. Ectomesenchyme between the tooth germs contained 23%, whilst the jaw ectomesenchyme contained 15% of proliferating cells. Bcl-2 expression had following pattern: strong in proliferating cells, moderate in tooth germs and dental crest, and weak in the ectomesenchyme. Bax co-expressed with Bcl-2 in the tooth germ and dental crest. In the reticulum and inner enamel epithelium Bcl-2 had prevalent expression, whilst Bax prevailed in the outer enamel epithelium and tooth ectomesenchyme.
Proliferating cells most likely influence growth of the tooth germ, Bcl-2 affects proliferation and differentiation of specific cell lineages, whilst Bax influences process of cell death.
研究增殖标志物 Ki-67、促凋亡 Bax 和抗凋亡 Bcl-2 蛋白在人牙早期发育过程中的时空表达。
使用 5-10 排卵后周龄的 8 个人类胚胎组织学切片进行 Ki-67、Bax 和 Bcl-2 标志物的免疫定位。通过计算 Ki-67 阳性细胞的分数来进行定量，以平均值 ± SD 表示，并通过 Mann-Whitney 检验、Kruskal-Wallis 和 Dunn 事后检验进行分析。
在 6-7 周发育时，牙胚和牙嵴含有 37%的增殖细胞，第 8 周增加到 40%，然后在第 10 周减少到 15%，而外间充质的增殖随后从 37%下降到 23%。釉质器的上皮部分显示出相似的增殖活性（31-36%），牙嵴 10%，而釉结没有增殖活性。牙外间充质含有更多的增殖细胞（50%）比下颌外间充质（35%），两者在第 10 周下降到 28%。牙胚之间的外间充质含有 23%，而下颌外间充质含有 15%的增殖细胞。Bcl-2 的表达模式如下：增殖细胞中表达强烈，牙胚和牙嵴中表达中度，外间充质中表达较弱。Bax 与牙胚和牙嵴中的 Bcl-2 共同表达。网状层和内釉上皮中 Bcl-2 表达普遍，而 Bax 在外釉上皮和牙外间充质中占优势。
增殖细胞很可能影响牙胚的生长，Bcl-2 影响特定细胞谱系的增殖和分化，而 Bax 影响细胞死亡过程。
