The Study Of Histology Of Organ Regeneration And Regeneration-related Gene Of Apostichopus Japonicus (Selenka)

The morphogenesis of tissues and organs has been considered the unsolved mysteries in developmental biology. The steps that lead to the assembly of an organ have proven difficult to dissect, partly because of the inherent complexity of the process and partly because most organ formation occurs during embryonic development, when multiple processes occur concomitantly, making the approaching to a particular process alone very difficult. Organogenesis can also occur in adult animals, although such process takes place to a much more limiting extent. Usually, the regeneration of an organ of adult animals functions only after its loss. In case of the occurrence, such regeneration can be separated spatially and temporally from developmental events, providing a model system for the study of organogenesis. One of the most striking cases of organogenesis in adult organisms is the regeneration of viscera in members of class Holothuroidea, to it Apostichopus japonicus belongs. A. japonicus is able to regenerate its internal body organs after evisceration. The development of a new digestive tract is a complex process involving changes that result in comprehensive alterations of cell structure, immune defense, signal transduction and gene expression.We proposed to use A. japonicus as a model for the decipherment of organogenesis by using available new modern biotechnology. Specimens of A. japonicus were collected in the northeast coast of Shandong province. Evisceration was induced by injecting 2-4ml of KCl 0.35mol/l into the coelom. We observed the evisceration and regeneration of A. japonicus by applying the method of histology. The result indicated that the A. japonicus started to regenerate immediately after the evisceration, and the respiratory trunk and the branched structure were observed on the 2nd day. The mesenteries gradually thickened after evisceration. The intestine epidermis and the muscular tissues were observed on the 5th day. A. japonicus needs 2 weeks to regenerate the newborn intestines.