Comizzoli Pierre, Ottinger Mary Ann
Smithsonian Conservation Biology Institute, National Zoological Park, Washington, DC, United States.
Department of Biology and Biochemistry, University of Houston, Houston, TX, United States.
Front Cell Dev Biol. 2021 May 19;9:680471. doi: 10.3389/fcell.2021.680471. eCollection 2021.
Similar to humans and laboratory animals, reproductive aging is observed in wild species-from small invertebrates to large mammals. Aging issues are also prevalent in rare and endangered species under human care as their life expectancy is longer than in the wild. The objectives of this review are to (1) present conserved as well as distinctive traits of reproductive aging in different wild animal species (2) highlight the value of comparative studies to address aging issues in conservation breeding as well as in human reproductive medicine, and (3) suggest next steps forward in that research area. From social insects to mega-vertebrates, reproductive aging studies as well as observations in the wild or in breeding centers often remain at the physiological or organismal scale (senescence) rather than at the germ cell level. Overall, multiple traits are conserved across very different species (depletion of the ovarian reserve or no decline in testicular functions), but unique features also exist (endless reproductive life or unaltered quality of germ cells). There is a broad consensus about the need to fill research gaps because many cellular and molecular processes during reproductive aging remain undescribed. More research in male aging is particularly needed across all species. Furthermore, studies on reproductive aging of target species in their natural habitat (sentinel species) are crucial to define more accurate reproductive indicators relevant to other species, including humans, sharing the same environment. Wild species can significantly contribute to our general knowledge of a crucial phenomenon and provide new approaches to extend the reproductive lifespan.
与人类和实验动物类似，从小型无脊椎动物到大型哺乳动物等野生动物中都观察到了生殖衰老现象。衰老问题在人类照料下的珍稀濒危物种中也很普遍，因为它们的预期寿命比在野外更长。本综述的目的是：（1）介绍不同野生动物物种生殖衰老的保守特征和独特特征；（2）强调比较研究在解决圈养繁殖和人类生殖医学中的衰老问题方面的价值；（3）提出该研究领域的下一步方向。从社会性昆虫到大型脊椎动物，生殖衰老研究以及在野外或繁殖中心的观察通常仍停留在生理或个体层面（衰老），而非生殖细胞层面。总体而言，多种特征在非常不同的物种中是保守的（卵巢储备的消耗或睾丸功能无下降），但也存在独特特征（无尽的生殖寿命或生殖细胞质量未改变）。人们普遍认为有必要填补研究空白，因为生殖衰老过程中的许多细胞和分子过程仍未得到描述。尤其需要在所有物种中对雄性衰老进行更多研究。此外，对目标物种在其自然栖息地（指示物种）的生殖衰老研究对于确定与包括人类在内的共享相同环境的其他物种相关的更准确生殖指标至关重要。野生动物可以极大地增进我们对这一关键现象的总体认识，并提供延长生殖寿命的新方法。
