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Studies on cell damage, healing and regeneration mechanism in insects using heavy-ion microbeams

利用重离子微束研究昆虫细胞损伤、愈合和再生机制

基本信息

批准号：
17380036
负责人：
KIGUCHI Kenji
金额：
$ 7.17万
依托单位：
Shinshu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

项目摘要

Previously we have developed the specific heavy-ion irradiation system for eggs, 4th and 5th instar larvae of the silkworm, Bomby mori. using heavy-ion microbeams with desired beam size and dose. In this study, we established a new irradiation method optimized for the first instar larvae. Now, we have completed heavy-ion irradiation methods available for all developmental stages of the insect, except for adult. Next, we studied the process and mechanism of degradation and regeneration of heavy-ion irradiated hemopoietic organs. As we previously demonstrated, locally-targeted irradiation of the larval hemopoietic organs of B. mori with heavy-ions causes serious cell damage, but subsequently these organs regenerate with high frequency. In this study we clarified that the circulating hemocytes could invade into the irradiated hemopoietic organs and eliminate the injured cells by phagocytosis. We also indicated that the stem cells responsible for regeneration might originate from the hemocytes (possibly prohemocytes) in circulation by implantation experiment of irradiated organs into the transgenic silkworms expressing GFP. On the other hand, we investigated the effects of heavy-ions on the differentiation of epidermal cells of the silkworm. Local targeted heavy-ion irradiation resulted in no marked morphological changes during larval stages, but the resultant moth loosed their scales in the irradiated site in a dose dependent manner. Moreover, it was shown that heavy-ion irradiation could suppress abnormal proliferation of epidermal cells in a mutant strain "Knobbed" (K). From these results it is suggested that epidermal cells are considerably resistant to heavy-ions and that epidermal differentiation is suppressed by inhibition of cell division after irradiation.

在此之前，我们已经开发了针对家蚕卵、4龄和5龄幼虫的特殊重离子辐照系统。使用具有所需光束大小和剂量的重离子微光束。在本研究中，我们建立了一种新的对一龄幼虫进行优化的辐照方法。目前，我们已经完成了除成虫外所有发育阶段的重离子辐照方法。接下来，我们研究了重离子辐照造血器官降解和再生的过程和机制。正如我们之前所证明的那样，用重离子局部靶向照射家蚕幼虫的造血器官会导致严重的细胞损伤，但随后这些器官会以高频率再生。在本研究中，我们阐明了循环血细胞可以侵入照射后的造血器官，并通过吞噬作用消灭受损细胞。我们还通过将辐照器官植入表达绿色荧光蛋白的转基因家蚕体内的实验表明，负责再生的干细胞可能来源于循环中的血细胞（可能是原血细胞）。另一方面，我们研究了重离子对家蚕表皮细胞分化的影响。局部靶向重离子照射后，幼虫形态无明显变化，但受照部位鳞片脱落呈剂量依赖性。此外，重离子辐照可以抑制突变株“knobs”(K)表皮细胞的异常增殖。这些结果表明，表皮细胞对重离子具有较强的抗性，辐照后细胞分裂受到抑制，从而抑制了表皮细胞的分化。