Jeffrey Jennifer D, Gilmour Kathleen M
Department of Biology, University of Ottawa, Ottawa, Ontario, Canada K1N 6N5
Department of Biology, University of Ottawa, Ottawa, Ontario, Canada K1N 6N5.
J Exp Biol. 2016 Jun 1;219(Pt 11):1734-43. doi: 10.1242/jeb.138826. Epub 2016 Apr 4.
The present study examined the effects of maternal social status, with subordinate status being a chronic stressor, on development and activity of the stress axis in zebrafish embryos and larvae. Female zebrafish were confined in pairs for 48 h to establish dominant/subordinate hierarchies; their offspring were reared to 144 h post-fertilization (hpf) and sampled at five time points over development. No differences were detected in maternal cortisol contribution, which is thought to be an important programmer of offspring phenotype. However, once zebrafish offspring began to synthesize cortisol de novo (48 hpf), larvae of dominant females exhibited significantly lower baseline cortisol levels than offspring of subordinate females. These lower cortisol levels may reflect reduced hypothalamic-pituitary-interrenal (HPI) axis activity, because corticotropin-releasing factor (crf) and cytochrome p450 side chain cleavage enzyme (p450scc) mRNA levels also were lower in larvae from dominant females. Moreover, baseline mRNA levels of HPI axis genes continued to be affected by maternal social status beyond 48 hpf. At 144 hpf, stress-induced cortisol levels were significantly lower in offspring of subordinate females. These results suggest programming of stress axis function in zebrafish offspring by maternal social status, emphasizing the importance of maternal environment and experience on offspring stress axis activity.
本研究考察了作为一种慢性应激源的母体社会地位对斑马鱼胚胎和幼体应激轴发育及活性的影响。将雌性斑马鱼成对饲养48小时以建立主导/从属等级制度；将它们的后代饲养至受精后144小时（hpf），并在发育过程中的五个时间点进行取样。在母体皮质醇贡献方面未检测到差异，而母体皮质醇被认为是后代表型的重要编程因素。然而，一旦斑马鱼后代开始从头合成皮质醇（48 hpf），主导雌性的幼体表现出的基线皮质醇水平显著低于从属雌性的后代。这些较低的皮质醇水平可能反映了下丘脑 - 垂体 - 肾间（HPI）轴活性降低，因为主导雌性幼体中促肾上腺皮质激素释放因子（crf）和细胞色素P450侧链裂解酶（p450scc）的mRNA水平也较低。此外，在48 hpf之后，HPI轴基因的基线mRNA水平继续受到母体社会地位的影响。在144 hpf时，从属雌性后代中应激诱导的皮质醇水平显著较低。这些结果表明母体社会地位对斑马鱼后代应激轴功能进行了编程，强调了母体环境和经历对后代应激轴活性的重要性。
