罗氏海盘车腕再生过程的组织学研究

Histological Examination of Arm Regeneration Process in Starfish Asterias rollestoni

对海盘车腕再生过程的研究,对于早日揭示棘皮动物等后口动物的再生机理具有重要意义。为了查清棘皮动物的再生方式及其机理,文中利用断腕创伤手术、组织化学和细胞化学技术对罗氏海盘车腕的再生过程进行了研究。连续跟踪研究结果表明,创伤8d后,在罗氏海盘车创伤腕的外表皮层和体腔上皮中均出现了干细胞原基样结构(blastemalikestructure)。创伤腕的伤口愈合过程是1个多事件同期发生的综合过程,首先是真皮层中脱分化的肌肉样细胞向创伤处迁移和聚集,经再分化和组织重排逐渐形成成熟的真皮层组织,然后是外表皮层和体腔上皮中的脱分化细胞向创伤处迁移分别形成明显加厚的前表皮层和前体腔上皮,最后再分别分化为成熟的表皮层和体腔上皮。而海盘车腕的再生过程则包括新生腕芽的延长和残腕的延长2个事件同期发生的过程。新生腕芽的生长与延长是在创伤愈合的基础上,依靠表皮层、体腔上皮和真皮层来源的脱分化细胞的迁移和再分化先形成新生腕芽,随后在新生腕芽上又出现了新的干细胞原基样结构,使腕芽逐渐生长和延长。而创伤刺激下残腕的延长,则是在形成干细胞原基样结构的基础上,在残腔体壁的许多部位形成多个横跨体壁的“楔状”干细胞原基样结构,这些结构的多点插入及其再分化形成新的体壁组织使残腕得以延长。本文的研究结果还显示,罗氏海盘车腕的再生同时采用了表变态再生和变形再生2种方式。

Studies on the regeneration process of amputated starfish arms are of great importance in the validation of the mechanisms of metazoan regeneration. To investigate the regeneration mechanisms of echinoderms, the detailed arm regeneration process in starfish Asterias rollestoni were examined by amputation techniques and staining methods of histochemistry and cytochemistry in this study. It was found that blastema-like structures, potential cell pools for the subsequent wound healing and arm regeneration, emerged from the outer epidermis and inner peritoneum near the tip of stumps 8 days after amputation. The wound healing process includes three kinds of contemporary events: 1) the dedifferentiated muscle-like cells under outer epidermis and inner peritoneum migrated and aggregated into the wound site, and redifferentiated into normal dermal tissues along with tissue rearrangements. 2) the dedifferentiated cells from outer epidermis migrated into the wound site to form a thickened pre-epidermis, and finally redifferentiated into mature outer epidermis. 3) the dedifferentiated cells from inner peritoneum migrated into the wound site to form a thickened pre-peritoneum, and finally redifferentiated into mature inner peritoneum. The arm regeneration process was executed via two different mechanisms, arm stump elongation and newly-generated arm-bud elongation. The elongation of arm stumps was carried out by formation and redifferentiation of a great many body wall-across blastema-like structures, while the elongation of newly-generated arm-buds was carried out by the gradual growth of the newly-generated arm-bud formed by the dedifferentiated cells from outer epidermis, inner peritoneum and dermis. Finally, it can be concluded that two regeneration manners, morphallaxis and epimorphosis, were both utilized in the arm regeneration process of Asterias rollestoni.