Department for Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna.
St. Anna Children's Cancer Research Institute (CCRI), Vienna.
Eur J Histochem. 2024 Feb 29;68(1):3977. doi: 10.4081/ejh.2024.3977.
During the aging process, cells can enter cellular senescence, a state in which cells leave the cell cycle but remain viable. This mechanism is thought to protect tissues from propagation of damaged cells and the number of senescent cells has been shown to increase with age. The speed of aging determines the lifespan of a species and it varies significantly in different species. To assess the progress of cellular senescence during lifetime, we performed a comparative longitudinal study using histochemical detection of the senescence-associated beta-galactosidase as senescence marker to map the staining patterns in organs of the long-lived zebrafish and the short-lived turquoise killifish using light- and electron microscopy. We compared age stages corresponding to human stages of newborn, childhood, adolescence, adult and old age. We found tissue-specific but conserved signal patterns with respect to organ distribution. However, we found dramatic differences in the onset of tissue staining. The stained zebrafish organs show little to no signal at newborn age followed by a gradual increase in signal intensity, whereas the organs of the short-lived killifish show an early onset of staining already at newborn stage, which remains conspicuous at all age stages. The most prominent signal was found in liver, intestine, kidney and heart, with the latter showing the most prominent interspecies divergence in onset of staining and in staining intensity. In addition, we found staining predominantly in epithelial cells, some of which are post-mitotic, such as the intestinal epithelial lining. We hypothesize that the association of the strong and early-onset signal pattern in the short-lived killifish is consistent with a protective mechanism in a fast growing species. Furthermore, we believe that staining in post-mitotic cells may play a role in maintaining tissue integrity, suggesting different roles for cellular senescence during life.
在衰老过程中，细胞可以进入细胞衰老状态，即细胞离开细胞周期但仍保持存活的状态。这种机制被认为可以保护组织免受受损细胞的增殖，并且已经证明衰老细胞的数量随着年龄的增长而增加。衰老的速度决定了物种的寿命，不同物种之间的差异很大。为了评估一生中细胞衰老的进展，我们使用组织化学检测衰老相关的β-半乳糖苷酶作为衰老标志物，进行了一项比较纵向研究，以描绘长寿斑马鱼和短命 turquoise 食蚊鱼的器官中染色模式，使用光镜和电子显微镜。我们比较了对应于人类新生儿期、儿童期、青春期、成年期和老年期的年龄阶段。我们发现，在器官分布方面存在组织特异性但保守的信号模式。然而，我们发现组织染色的起始存在显著差异。染色的斑马鱼器官在新生儿期几乎没有信号，随后信号强度逐渐增加，而短命食蚊鱼的器官在新生儿期就已经出现早期染色，并且在所有年龄阶段都很明显。最明显的信号出现在肝脏、肠道、肾脏和心脏，后者在染色起始和染色强度方面表现出最显著的种间差异。此外，我们发现染色主要存在于上皮细胞中，其中一些是有丝分裂后细胞，如肠道上皮衬里。我们假设，短命食蚊鱼中强烈且早期出现的信号模式与快速生长物种中的保护机制有关。此外，我们认为有丝分裂后细胞的染色可能在维持组织完整性方面发挥作用，这表明细胞衰老在生命过程中可能发挥不同的作用。
