Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, United States of America.
Cancer Metabolism and Microenvironment Program, Sanford Burnham Prebys, La Jolla, CA, United States of America.
PLoS One. 2024 Sep 12;19(9):e0302673. doi: 10.1371/journal.pone.0302673. eCollection 2024.
Mechanical stress is a measure of internal resistance exhibited by a body or material when external forces, such as compression, tension, bending, etc. are applied. The study of mechanical stress on health and aging is a continuously growing field, as major changes to the extracellular matrix and cell-to-cell adhesions can result in dramatic changes to tissue stiffness during aging and diseased conditions. For example, during normal aging, many tissues including the ovaries, skin, blood vessels, and heart exhibit increased stiffness, which can result in a significant reduction in function of that organ. As such, numerous model systems have recently emerged to study the impact of mechanical and physical stress on cell and tissue health, including cell-culture conditions with matrigels and other surfaces that alter substrate stiffness and ex vivo tissue models that can apply stress directly to organs like muscle or tendons. Here, we sought to develop a novel method in an in vivo model organism setting to study the impact of altering substrate stiffness on aging by changing the stiffness of solid agar medium used for growth of C. elegans. We found that greater substrate stiffness had limited effects on cellular health, gene expression, organismal health, stress resilience, and longevity. Overall, our study reveals that altering substrate stiffness of growth medium for C. elegans has only mild impact on animal health and longevity; however, these impacts were not nominal and open up important considerations for C. elegans biologists in standardizing agar medium choice for experimental assays.
机械应力是指当外部力（如压缩、拉伸、弯曲等）施加于物体或材料时，其表现出的内部阻力的一种度量。研究机械应力对健康和衰老的影响是一个不断发展的领域，因为细胞外基质和细胞间黏附的重大变化可能导致组织在衰老和患病条件下的硬度发生显著变化。例如，在正常衰老过程中，包括卵巢、皮肤、血管和心脏在内的许多组织的硬度增加，这可能导致该器官功能显著下降。因此，最近出现了许多模型系统来研究机械和物理应激对细胞和组织健康的影响，包括使用基质胶和其他改变基质硬度的表面的细胞培养条件，以及可以直接向肌肉或肌腱等器官施加应激的离体组织模型。在这里，我们试图在体内模式生物环境中开发一种新方法，通过改变用于秀丽隐杆线虫生长的固体琼脂培养基的硬度来研究改变基质硬度对衰老的影响。我们发现，较高的基质硬度对细胞健康、基因表达、生物体健康、应激弹性和寿命的影响有限。总的来说，我们的研究表明，改变秀丽隐杆线虫生长培养基的基质硬度对动物健康和寿命的影响很小；然而，这些影响并不是微不足道的，这为秀丽隐杆线虫生物学家在标准化实验琼脂培养基选择方面提供了重要的考虑因素。
