Beaulieu Michaël, Benoit Laure, Abaga Steven, Kappeler Peter M, Charpentier Marie J E
Zoological Institute and Museum, University of Greifswald, Greifswald, Germany.
CIRAD, Montpellier Cedex 5, France.
Mol Ecol. 2017 Oct;26(20):5603-5613. doi: 10.1111/mec.14329. Epub 2017 Sep 8.
Leucocytes are typically considered as a whole in studies examining telomere dynamics in mammals. Such an approach may be precarious, as leucocytes represent the only nucleated blood cells in mammals, their composition varies temporally, and telomere length differs between leucocyte types. To highlight this limitation, we examined here whether seasonal variation in leucocyte composition was related to variation in telomere length in free-ranging mandrills (Mandrilllus sphinx). We found that the leucocyte profile of mandrills varied seasonally, with lower lymphocyte proportion being observed during the long dry season presumably because of the combined effects of high nematode infection and stress at that time of the year. Interestingly, this low lymphocyte proportion during the long dry season was associated with shorter telomeres. Accordingly, based on longitudinal data, we found that seasonal changes in lymphocyte proportion were reflected by corresponding seasonal variation in telomere length. Overall, these results suggest that variation in lymphocyte proportion in blood can significantly affect telomere measurements in mammals. However, lymphocyte proportion did not entirely explain variation in telomere length. For instance, a lower lymphocyte proportion with age could not fully explain shorter telomeres in older individuals. Overall, our results show that telomere length and leucocyte profile are strongly although imperfectly intertwined, which may obscure the relationship between telomere dynamics and ageing processes in mammals.
在研究哺乳动物端粒动态变化时，白细胞通常被视为一个整体。这种方法可能不太可靠，因为白细胞是哺乳动物唯一的有核血细胞，其组成随时间变化，而且不同类型白细胞的端粒长度也不同。为了突出这一局限性，我们在此研究了自由放养的山魈（Mandrilllus sphinx）白细胞组成的季节性变化是否与端粒长度的变化有关。我们发现，山魈的白细胞谱存在季节性变化，在漫长的旱季，淋巴细胞比例较低，推测这是由于该季节线虫感染率高和压力大共同作用的结果。有趣的是，漫长旱季中较低的淋巴细胞比例与较短的端粒有关。因此，基于纵向数据，我们发现淋巴细胞比例的季节性变化反映在端粒长度的相应季节性变化上。总体而言，这些结果表明，血液中淋巴细胞比例的变化会显著影响哺乳动物的端粒测量。然而，淋巴细胞比例并不能完全解释端粒长度的变化。例如，随着年龄增长淋巴细胞比例降低并不能完全解释老年个体端粒较短的现象。总体而言，我们的结果表明，端粒长度和白细胞谱虽然紧密但并不完美地相互交织，这可能会掩盖哺乳动物中端粒动态变化与衰老过程之间的关系。
