Mladenov Philip V, Bisgrove Brent, Asotra Satish, Burke Robert D
Department of Biology, Mount Allison University, E0A3C0, Sackville, N.B., Canada.
Department of Biology, University of Victoria, V8W 2Y2, Victoria, B.C., Canada.
Rouxs Arch Dev Biol. 1989 May;198(1):19-28. doi: 10.1007/BF00376366.
Wound healing and regeneration following amputation of arm-tips of the sea star, Leptasterias hexactis, are described using light microscopy, SEM, TEM, and [H] thymidine autoradiography. The process can be divided into a number of stages. Initially, the wound is closed by contractions of the stump-tip. Re-epithelialization then occurs through migration of epidermal cells from adjacent areas over the wound to form a thin wound epidermis. This is converted into a thicker, permanent covering in concurrence with the onset of cell cycle activity in the wound epidermis and adjacent epidermal regions. Histolysis and phagocytosis of damaged tissues occur beneath the new epidermis and a small connective tissue scar develops at the wound site within which muscle differentiates. At this time, elevated levels of [H]thymidine incorporation are initiated in the sub-epidermal tissues of the arm-tip. A variety of differentiated cell types enter the cell cycle including cells of the parietal peritoneum, lining of the radial water canal, and the dermis. Cell division is accompanied by the development of a small new arm-tip complete with terminal ossicle, terminal tentacle, and optic cushion. The radial water canal, radial nerve, and perivisceral coelom extend by outgrowth into this newly developing tip. Accelerated growth of the regenerate then occurs in a zone just proximal to the new tip. There is no evidence of a blastema-like mass of rapidly dividing undifferentiated cells at the tip of regenerating arms. Arm-tip regeneration in this sea star may therefore be best described as a morphallactic-like process in which a true blastema is not formed, but in which scattered cell proliferation plays an essential role.
利用光学显微镜、扫描电子显微镜、透射电子显微镜和[H]胸腺嘧啶核苷放射自显影技术，描述了六腕海星（Leptasterias hexactis）腕尖截肢后的伤口愈合和再生过程。该过程可分为多个阶段。最初，伤口通过残端收缩闭合。然后，表皮细胞从伤口周围区域迁移，重新上皮化，在伤口上形成一层薄的伤口表皮。随着伤口表皮和相邻表皮区域细胞周期活动的开始，这层表皮转化为更厚的永久性覆盖物。受损组织的组织溶解和吞噬作用在新表皮下方发生，伤口部位形成一个小的结缔组织瘢痕，肌肉在其中分化。此时，腕尖表皮下组织中[H]胸腺嘧啶核苷掺入水平升高。多种分化细胞类型进入细胞周期，包括体腔腹膜细胞、辐射水管内衬细胞和真皮细胞。细胞分裂伴随着一个小的新腕尖的发育，新腕尖带有末端小骨、末端触手和视垫。辐射水管、辐射神经和围脏腔通过向外生长延伸到这个新发育的尖端。然后，在新尖端近端的一个区域，再生部分加速生长。在再生腕尖处没有证据表明存在类似胚基的快速分裂的未分化细胞团。因此，这种海星的腕尖再生最好被描述为一种类似形态再生的过程，其中不会形成真正的胚基，但分散的细胞增殖起着至关重要的作用。
