Abstract：
In recent years, there has been a burgeoning interest in exploring the nuances of animal stress physiology, particularly in relation to parameters such as sex and behavioral phenotype-dependent variations, which is crucial for understanding phenotypic variation and its role in evolutionary selection. However, a significant dearth remains in how chronic stressors affect organismal stress physiology concerning the aforesaid parameters. This void is even wider pertaining to the response of peripheral tissues, such as the skin, the organ with the highest surface contact area with the environment. Hence, we behaviorally grouped the zebrafishes based on their boldness and the body condition, whole body cortisol response, along with examining the transcriptional response, global DNA methylome, and oxidative DNA damage in the skin upon chronic crowding. Upon baseline conditions, clear distinction between bold and shy phenotypes was found, particularly in males. The boldness index score distribution exhibited greater uniformity in males than in females. Regarding the body condition response to chronic crowding, shy males showed a significant relative decline compared with their bold counterparts, while this trend did not hold true for females. qPCR data revealed distinctive expression patterns in key genes that play critical roles in cellular processes such as stress-mediated gene regulation, immune response, oxidative stress protection, and maintenance of genomic integrity through epigenetic modifications across behavioral phenotypes and sexes under both with and without chronic crowding stress. Global DNA methylation levels significantly declined only in chronically crowded shy males, and sex/behavioral phenotype-dependent trends in oxidative DNA damage were identified.NEW & NOTEWORTHY This paper analyzes the response of zebrafish to crowding stress through a new approach focused on the peripheral response dynamics of the skin, the main mucosal tissue, and involving sex and behavioral phenotype influences. Shy males showed significant distress as observed by body condition, physiological and transcriptional response, and global DNA methylation. Nuances in stress response across behavioral phenotypes and sex indicate a genetic and behavioral specificity and further inherent epigenetic regulatory dimension.
摘要：
近年来,人们对探索动物应激生理学的细微差别越来越感兴趣，特别是关于性别等参数，和行为表型相关的变异，这对于理解表型变异及其在进化选择中的作用至关重要。然而,关于上述参数，慢性应激源如何影响机体应激生理学仍然存在很大的不足。与外周组织的反应有关的空隙甚至更宽，比如皮肤，与环境接触面积最高的器官。因此，我们根据斑马鱼的胆量和身体状况对它们进行行为分组，全身皮质醇反应，同时检查转录反应，全球DNA甲基化，慢性拥挤时皮肤的DNA氧化损伤。在基线条件下，明确区分粗体和害羞的表型被发现，尤其是男性。男性的大胆指数得分分布比女性的均匀性更高。关于身体状况对慢性拥挤的反应，与大胆的男性相比，害羞的男性表现出明显的相对下降，虽然这种趋势对女性来说并不成立。qPCR数据揭示了关键基因的独特表达模式，这些基因在细胞过程中发挥关键作用，如应激介导的基因调控，免疫反应，氧化应激保护，在有和没有慢性拥挤压力的情况下，通过跨行为表型和性别的表观遗传修饰来维持基因组完整性。全球DNA甲基化水平仅在长期拥挤的害羞男性中显着下降，并确定了氧化DNA损伤的性别/行为表型依赖性趋势。
