Programmed cell death in the regenerating deer antler
Programmed cell death in the regenerating deer antler
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DOI：
10.1111/j.1469-7580.2005.00464.x
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发表时间：
2005-10-01
影响因子：
2.4
通讯作者：
Price, JS
中科院分区：
文献类型：
--
作者：
Colitti, M;Allen, SP;Price, JS
鹿角是哺乳动物唯一能够进行表型再生的附肢，因此为研究哺乳动物再生的机制提供了一个独特的模型。鹿角通过改良的软骨内骨化过程延长，同时膜内骨化发生在鹿角轴周围。在这项研究中，凋亡的网站在生长中的鹿角尖被确定为TUNEL染色和相关的细胞增殖，由PCNA染色确定。Bcl-2和Bax通过RT-PCR鉴定，Bax也在组织切片中免疫定位。软骨膜、未分化间充质细胞和细胞性骨膜的凋亡指数较高，而皮肤的凋亡指数较低。间充质、皮肤（特别是毛囊）和细胞骨膜的增殖指数较高;纤维软骨膜和骨膜的增殖指数较低，软骨中几乎检测不到。bcl-2和bax在软骨膜/间充质和非矿化软骨中的表达高于皮肤和矿化软骨。Bax免疫定位于间充质细胞、软骨祖细胞、软骨细胞、成骨细胞、骨细胞和破骨细胞。总之，这项研究表明，程序性细胞死亡在鹿角再生中发挥着必要的作用，就像在骨骼发育、骨骼生长和骨骼重塑过程中一样。间充质祖细胞中高水平的凋亡和增殖证实了这代表了鹿茸的“生长区”。事实上，间充质生长区中TUNEL阳性细胞的百分比（高达64%）高于任何其他成人组织中记录的百分比。这种广泛的细胞死亡可能反映了生长中的鹿角发生的形态发生和组织重塑的惊人速度。控制鹿茸组织中细胞生长和凋亡之间平衡的局部和/或全身因素现在需要确定。
Antlers are the only mammalian appendages capable of epimorphic regeneration and thus provide a unique model for investigating the mechanisms that underlie mammalian regeneration. Antlers elongate by a modified endochondral ossification process while intramembranous ossification takes place concurrently around the antler shaft. In this study, sites of apoptosis in the growing antler tip were identified by TUNEL staining and related to cell proliferation, as determined by PCNA staining. Bcl-2 and bax were identified by RT-PCR and bax was also immunolocalized in tissue sections. The apoptotic index was high in perichondrium, undifferentiated mesenchymal cells and cellular periosteum but was low in skin. The proliferation index was high in mesenchyme, skin (specifically in hair follicles) and cellular periosteum; it was low in fibrous perichondrium and periosteum, and barely detectable in cartilage. Both bcl-2 and bax were found to be more highly expressed in the perichondrium/mesenchyme and non-mineralized cartilage than in skin and mineralized cartilage. Bax was immunolocalized in mesenchyme cells, chondroprogenitors, chondrocytes, osteoblasts, osteocytes and osteoclasts. In conclusion, this study shows that programmed cell death plays a necessary role in regenerating antlers, as it does during skeletal development, bone growth and bone remodelling. The high level of apoptosis and proliferation in mesenchymal progenitor cells confirms that this represents the antler 'growth zone'. In fact, the percentage of TUNEL-positive cells in the mesenchymal growth zone (up to 64%) is higher than that recorded in any other adult tissue. This extensive cell death probably reflects the phenomenal rate of morphogenesis and tissue remodelling that takes place in a growing antler. The local and/or systemic factors that control the balance between cell growth and apoptosis in antler tissues now need to be determined.