Hibernators suppress physiological processes when expressing torpor, yet little is known about the effects of torpor on male reproductive physiology. Studies of hibernating mammals suggest that deep torpor negatively impacts spermatogenesis and that transitions between torpor and euthermic arousals increase cellular oxidative stress, with potentially damaging effects on sperm. Here, we hypothesize that variation in torpor expression affects the reproductive readiness of hibernators by impacting their sperm production. To test this, we examined the relationship between torpor expression and spermatogenesis in captive eastern chipmunks (Tamias striatus). We determined torpor depth with temperature data loggers and assessed its relationship with spermatogenesis by examining spermatogenic progression, cell division, sperm counts, sperm maturity, and DNA damage. We show that deep hibernators (high levels of torpor) largely halted spermatogenesis in late hibernation in comparison to shallow hibernators (low levels of torpor), where ongoing spermatogenesis was observed. Despite these differences in spermatogenic state during hibernation, spermatogenic progression, sperm numbers, and maturity did not differ in spring, potentially reflecting similar degrees of reproductive readiness. Interestingly, shallow hibernators exhibited higher rates of DNA damage in spermatogenic cells during hibernation, with this trend reversing in spring. Our results thus indicate that, once heterothermy is terminated, deep hibernators resume spermatogenesis, but are characterized by higher rates of DNA damage in spermatogenic cells at the seasonal stage when spring mating commences. Therefore, our study confirmed post-hibernation recovery of sperm production but also a potential impact of deep torpor expression during winter on DNA damage in spring.

中文翻译：

---

Torpor 表达与冬眠的东部花栗鼠的精子发生差异有关。

冬眠者在表达麻木时会抑制生理过程，但人们对麻木对男性生殖生理的影响知之甚少。对冬眠哺乳动物的研究表明，深度麻木对精子发生产生负面影响，并且麻木和正常唤醒之间的过渡会增加细胞氧化应激，对精子有潜在的破坏作用。在这里，我们假设麻木表达的变化通过影响它们的精子产生来影响冬眠者的生殖准备。为了测试这一点，我们检查了圈养东部花栗鼠（Tamias striatus）的麻木表达和精子发生之间的关系。我们用温度数据记录器确定了麻木深度，并通过检查生精过程、细胞分裂、精子数量、精子成熟度、和 DNA 损伤。我们表明，与观察到正在进行的精子发生的浅冬眠者（低水平的麻木）相比，深冬眠者（高水平的麻木）在很大程度上停止了冬眠后期的精子发生。尽管冬眠期间生精状态存在这些差异，但春季生精进程、精子数量和成熟度没有差异，这可能反映了相似的生殖准备程度。有趣的是，浅冬眠者在冬眠期间在生精细胞中表现出更高的 DNA 损伤率，这种趋势在春季逆转。因此，我们的结果表明，一旦异温终止，深冬眠者就会恢复精子发生，但其特征是在春季交配开始的季节性阶段，生精细胞的 DNA 损伤率较高。所以，