Murray Gisela, García-Arrarás José E
Biology Department, University of Puerto Rico, 00931, Rio Piedras, PR, 00931, Puerto Rico.
Cell Tissue Res. 2004 Dec;318(3):515-24. doi: 10.1007/s00441-004-0978-3. Epub 2004 Oct 5.
Echinoderms are well known as being able to regenerate body parts and thus provide excellent models for studying regenerative processes in adult organisms. We are interested in intestinal regeneration in the sea cucumber, Holothuria glaberrima, and focus here on the regeneration of intestinal muscle components. We have used immunohistochemical techniques to describe the formation of the intestinal muscle layers. Myoblasts are first observed within the regenerating structure, adjacent to the coelomic epithelia. Within a few days, these cells acquire muscle markers and form a single cell layer that underlies the epithelia. Animals injected with BrdU at various regeneration stages have been subsequently analyzed for the presence of muscle differentiation markers. BrdU-labeled muscle nuclei are observed in myocytes of 3-week regenerates, showing that these cells originate from proliferating precursors. The peak in muscle precursor proliferation appears to occur during the second week of regeneration. Therefore, new muscle cells in the regenerating intestine originate from precursors that have undergone cell division. Our results suggest that the precursor cells arise from the coelomic epithelia. We also provide a comparative view of muscle regeneration in an echinoderm, a topic of interest in view of the many recent studies of muscle regeneration in vertebrate species.
棘皮动物以能够再生身体部位而闻名，因此为研究成体生物的再生过程提供了绝佳模型。我们对光滑海参（Holothuria glaberrima）的肠道再生感兴趣，在此聚焦于肠道肌肉成分的再生。我们运用免疫组织化学技术描述了肠道肌肉层的形成。成肌细胞首先在再生结构中被观察到，紧邻体腔上皮。在几天内，这些细胞获得肌肉标记物并形成位于上皮下方的单细胞层。在不同再生阶段注射了BrdU的动物随后被分析肌肉分化标记物的存在情况。在3周龄再生体的肌细胞中观察到BrdU标记的肌肉细胞核，表明这些细胞起源于增殖前体。肌肉前体增殖的峰值似乎出现在再生的第二周。因此，再生肠道中的新肌肉细胞起源于经历了细胞分裂的前体细胞。我们的结果表明前体细胞起源于体腔上皮。鉴于最近对脊椎动物物种肌肉再生的众多研究，我们还提供了棘皮动物肌肉再生的比较观点。
