Diurnal rhythm of human semen quality: analysis of large-scale human sperm bank data and timing-controlled laboratory study

Abstract

STUDY QUESTION Can we identify diurnal oscillations in human semen parameters as well as peak times of semen quality? SUMMARY ANSWER Human semen parameters show substantial diurnal oscillation, with most parameters reaching a peak between 1100 and 1500 h. WHAT IS KNOWN ALREADY A circadian clock appears to regulate different physiological functions in various organs, but it remains controversial whether diurnal rhythms occur in human semen parameters. STUDY DESIGN, SIZE, DURATION The medical record of a provincial human sperm bank (HSB) with 33 430 semen samples collected between 0800 and 1700 h from 1 March 2010 to 8 July 2015 was used to analyze variation in semen parameters among time points. A laboratory study was conducted to collect semen samples (n = 36) from six volunteers at six time points with identical time intervals (2 days plus 4 h) between 6 June and 8 July in 2019, in order to investigate the diurnal oscillation of semen parameters in vivo, with a strictly controlled abstinence period. Therefore, the sperm bank study with a large sample size and the in vivo study with a strictly controlled abstinence period in a 24-h time window could be compared to describe the diurnal rhythms in human semen parameters. PARTICIPANTS/MATERIALS, SETTING, METHODS Samples were obtained from potential HSB donors and from participants in the laboratory study who were volunteers, recruited by flyers distributed in the community. Total sperm count, sperm concentration, semen volume, progressive motility and total motility were assessed using computer-aided sperm analysis. In addition, sperm chromatin integrity parameters (DNA fragmentation index and high DNA stainability) were assessed by the sperm chromatin structure assay, and sperm viability was measured with flow cytometry in the laboratory study. MAIN RESULTS AND THE ROLE OF CHANCE The 33 430 samples from the HSB showed a temporal variation in total sperm count, sperm concentration, semen volume, progressive motility and total motility (all P < 0.001) between 0800 and 1700 h. Consequently, the eligibility of semen samples for use in ART, based on bank standards, fluctuated with time point. Each hour earlier/later than 1100 h was associated with 1.14-fold risk of ineligibility. Similarly, the 36 samples taken during the 24-h time window showed diurnal oscillation. With the pre-collection abstinence period strictly controlled, most semen parameters reached the most favorable level between 1100 and 1500 h. LIMITATIONS, REASONS FOR CAUTION Some of the possible confounding factors, such as energy intake, which might influence semen quality or diurnal rhythms, were not adjusted for in the analyses. In addition, the findings should be considered with caution because the study was conducted in a specific population, time and place, while the timing of oscillations could differ with changing conditions. WIDER IMPLICATIONS OF THE FINDINGS The findings could help us to estimate semen quality more precisely and to obtain higher quality sperm for use in ART and in natural conception. STUDY FUNDING/COMPETING INTEREST(S) This study was supported by the National Natural Science Foundation of China (81871208) and National Key R&D Program of China (2017YFC1002001). There are no conflicts of interest to declare. TRIAL REGISTRATION NUMBER N/A.

Learning Appreciation By Innovation (L.A.B.I.) Model: BANKING ON THE ATMs OF SPEECH WRITING

“…It demands not just technical prowess, but also a profound grasp of rhetoric, audience enchantment, and the art of persuasion. While conventional pedagogy has often emphasized the structural underpinnings and rhetorical devices of speech writing, it has frequently overlooked the enchanting and innovative facets of this craft (Liu et al, 2022).…”

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“…The ensuing chapters will plunge even deeper into the intricacies of the L.A.B.I. Model, dissecting its components, unveiling its implementation, and unveiling its transformative impact on the craft of speech writing and the appreciation thereof (Liu et al, 2022).…”

Male fertility: a summary overview of the publications October 2022 – March 2023

“…однако в отношении сперматогенеза это может быть не так, потому что сперматозоиды формируются на протяжении 2,5 -3,0 месяцев и конкретный образец эякулята -итог данного длительного процесса. Китайские авторы в рамках масштабного исследования изучили вариабельность параметров спермограммы у доноров спермы в зависимости от времени суток, когда доноры сдавали анализ [6].…”