环境内分泌干扰物对斑马鱼组织修复与再生的影响

Tissue damages are unavoidable for multicellular organisms across the whole life span. Injury, disease and aging all result in a loss of tissue and reduce quality of life. Therefore, restoration of tissue morphology and function is fundamental for the fitness of individuals, as well as the maintenance of ecological system. It is now evidentially demonstrated that the presence of certain pollutants can interfere with the tissue repair and regeneration process of teleosts, which potentially being the consequence of the disruption of their immune system. Considering the effects of endocrine disrupting chemicals (EDCs) on the immune system of exposed organisms, and the important role of immune system for tissue repair and regeneration, it is reasonable to hypothesize that EDCs will disrupt the process of tissue repair and regeneration, impair fitness, and result in the decline of fish population. To achieve this purpose, the caudal fin in zebrafish larvae will be amputated to represent the various tissue damages occurred in fish, and the effects of EDCs on the tissue repair and regeneration of exposed organism will be studied. Therefore, in this project, firstly, a caudal fin regeneration model in zebrafish larvae will be built, and the physiological and biochemical processes of wound healing and tissue regeneration will be investigated. Secondly, the impacts of synthetic EDCs on caudal fin regeneration in zebrafish larvae will be evaluated following the exposure with representative estrogen or androgen, respectively. Moreover, with an emphasis on the relationship among endocrine system, immune system, and tissue repair or regeneration, the potential targets or signaling networks will be explored in-depth by the aid of various molecular biology techniques, such as RNA sequencing, gene knockdown, etc, which expanding our understanding of the cellular and molecular mechanisms. The results of this project will not only provide a new perspective for assessing the ecotoxicity of pollutants on aquatic organisms, but also be rationally extrapolated to mammals including humans, based on the conservation of cellular and molecular mechanism in tissue regeneration across species, and pave the way toward a comprehensive assessment and regulation for environmental pollutants.

生物体在整个生命周期中，组织损伤是无法避免的，而组织修复和再生能力对于生物极为重要，具有显著的生态意义。研究发现环境污染物的暴露将影响硬骨鱼的组织修复和再生，而这很可能是通过免疫系统而产生作用的。鉴于环境内分泌干扰物对于免疫系统的影响以及免疫系统对于组织修复和再生的重要作用，我们有理由推断，环境内分泌干扰物可通过干扰鱼类组织再生过程而损害其在环境中的生存能力，进而降低其种群数量。因此，本课题拟通过斑马鱼幼鱼的尾鳍再生模型，研究典型环境内分泌干扰物对鱼类组织再生能力的影响，并以内分泌系统——免疫系统——组织修复与再生为主线，借助转录组深度测序、基因敲降等分子生物学技术手段，探讨可能的靶位点和信号通路，初步阐明其作用机理。本研究不但为评价化合物的水生生态毒性提供了崭新的视角，而鉴于组织再生过程中分子机理上的保守性，其结果更可以合理外推至哺乳类乃至人类，从而为相关污染物的管控提供科学的依据。

对于包括鱼类在内的野生生物而言，在其整个生命周期中，组织损伤是无法避免的，而具有一定的组织修复与再生能力，从而有效地保持其内稳态，对于所有生物个体乃至种群而言均极为重要。研究表明，组织修复与再生过程是由多个信号通路共同调控的，而免疫系统也发挥了关键作用。鉴于环境内分泌干扰物对于免疫系统的影响，我们有理由推断环境内分泌干扰物也可以干扰鱼类的组织再生过程。因此，项目借助于斑马鱼尾鳍再生模型，研究典型内分泌干扰物对鱼类组织和再生的影响以及机理。首先，建立斑马鱼尾鳍再生模型，以免疫系统以及组织修复为重点，在基因、蛋白、细胞和组织等不同生物学水平揭示了尾鳍伤口愈合以及形态功能重建过程中的生物学过程，为后续研究研究提供了较为清晰的生物学背景。其次，基于已建立的斑马鱼尾鳍再生模型，以内分泌系统-免疫系统-组织修复与再生为主线，研究了雌激素受体激动剂、雄激素受体激动剂、糖皮质激素、甲状腺激素等内分泌干扰物对斑马鱼尾鳍再生的影响，确认了部分内分泌干扰物可以通过影响生物的免疫功能，从而抑制生物的组织修复与再生能力，最终降低生物在环境中的适应性。再次，通过与受体拮抗剂的共暴露等方式，研究了雌激素和雄激素等两类最为典型的内分泌干扰物影响组织修复与再生能力的靶位点和信号通路，初步阐明了以激素受体的结合与激活为起始事件，以尾鳍再生能力的抑制为有害结局的完整毒理学过程。最后，借鉴斑马鱼幼鱼尾鳍再生模型，通过尾鳍扎针激活鱼体免疫系统，构建了斑马鱼幼鱼免疫毒性检测模型；同时以斑马鱼尾鳍再生模型为毒性检测手段，初步探讨了微纳塑料、蓝藻代谢产物等其他环境污染物对于不健康状态下水生生物的毒性效应。上述结果不但确认了若干典型环境内分泌干扰物影响鱼类组织修复与再生的毒性效应与作用机理，从而为评价化合物的生态毒性提供新视角；同时，所建立的斑马鱼幼鱼毒性检测体系在化学品和环境污染物的毒性筛查和甄别中具有一定的应用前景。