Nematology Unit, Department of Biology, Ghent University, Ledeganckstraat 35, 9000 Ghent, Belgium.
Front Zool. 2009 Jul 30;6:15. doi: 10.1186/1742-9994-6-15.
Free-living flatworms ("Turbellaria") are appropriate model organisms to gain better insight into the role of stem cells in ageing and rejuvenation. Ageing research in flatworms is, however, still scarce. This is partly due to culture difficulties and the lack of a complete set of demographic data, including parameters such as median lifespan and age-specific mortality rate. In this paper, we report on the first flatworm survival analysis. We used the species Macrostomum lignano, which is an emerging model for studying the reciprocal influence between stem cells, ageing and rejuvenation. This species has a median lifespan of 205 +/- 13 days (average +/- standard deviation [SD]) and a 90th percentile lifespan of 373 +/- 32 days. The maximum lifespan, however, is more than 745 days, and the average survival curve is characterised by a long tail because a small number of individuals lives twice as long as 90% of the population. Similar to earlier observations in a wide range of animals, in M. lignano the age-specific mortality rate increases exponentially, but levels off at the oldest ages. To compare the senescence of M. lignano with that of other ageing models, we determined the mortality rate doubling time, which is 0.20 +/- 0.02 years. As a result, we can conclude that M. lignano shows gradual senescence at a rate similar to the vertebrate ageing models Rattus norvegicus and Mus musculus. We argue that M. lignano is a suitable model for ageing and rejuvenation research, and especially for the role of stem cells in these processes, due to its accessible stem cell system and regeneration capacity, and the possibility of combining stem cell studies with demographic analyses.
自由生活的扁形动物（“涡虫”）是研究干细胞在衰老和恢复活力中作用的合适模式生物。然而，扁形动物的衰老研究仍然很少。这部分是由于培养困难和缺乏完整的人口统计数据，包括中位寿命和特定年龄死亡率等参数。在本文中，我们报告了第一个扁形动物生存分析。我们使用了 Macrostomum lignano 物种，该物种是研究干细胞、衰老和恢复活力之间相互影响的新兴模型。该物种的中位寿命为 205 +/- 13 天（平均值 +/- 标准偏差 [SD]），90%寿命为 373 +/- 32 天。然而，最大寿命超过 745 天，平均生存曲线的特点是长尾，因为少数个体的寿命是人口的 90%的两倍。与在广泛的动物中早期观察到的相似，在 M. lignano 中，特定年龄死亡率呈指数增长，但在最老的年龄趋于平稳。为了将 M. lignano 的衰老与其他衰老模型进行比较，我们确定了死亡率倍增时间，即 0.20 +/- 0.02 年。因此，我们可以得出结论，M. lignano 以类似于脊椎动物衰老模型 Rattus norvegicus 和 Mus musculus 的速度表现出逐渐衰老。我们认为，由于其可访问的干细胞系统和再生能力，以及将干细胞研究与人口统计分析相结合的可能性，M. lignano 是衰老和恢复活力研究以及干细胞在这些过程中的作用的合适模型。
