Adverse effects of paternal obesity on the motile spermatozoa quality

Growing evidence suggests that paternal obesity may decrease male fertility potential. During infertility treatment with intra-cytoplasmic sperm injection (ICSI), a morphologically normal motile spermatozoon is injected into a mature egg, when possible. However, sperm motility and morphology per se do not reflect the sperm molecular composition. In this study, we aimed to assess the quality of motile spermatozoa in the context of obesity by analysing their conventional and molecular characteristics as well as their ability to promote early embryonic development. A prospective study was conducted on 128 infertile men divided into three groups: 40 lean, 42 overweight, and 46 obese men. Conventional sperm parameters (concentration, motility and morphology) and sperm molecular status (chromatin composition and integrity, 5-methycytosine (5-mC) and 5-hydroxycytosine (5-hmC) contents and oxidative stress level) were analysed on raw semen and/or on motile spermatozoa selected by density gradient or swim-up techniques. Morphokinetic analysis of the embryos derived from ICSI was performed using the Embryoviewer software. Our results showed that the motile sperm-enriched fraction from obese men exhibited higher levels of retained histones (p越来越多的证据表明，父亲肥胖可能降低男性生育潜能。在采用卵胞浆内单精子注射（intra-cytoplasmic sperm injection, ICSI）进行不育治疗时，若条件允许，会将形态正常的活动精子注射入成熟卵母细胞中。然而，精子活力与形态本身并不能反映精子的分子组成。本研究旨在通过分析活动精子的常规与分子特征，以及其促进早期胚胎发育的能力，评估肥胖背景下活动精子的质量。本研究采用前瞻性研究设计，纳入128名不育男性，将其分为3组：体瘦组40例、超重组42例、肥胖组46例。研究人员分别对原精液以及/或经密度梯度或上游法（swim-up）分选富集的活动精子，检测了其常规精子参数（浓度、活力与形态）与精子分子状态（染色质组成与完整性、5-甲基胞嘧啶（5-methycytosine, 5-mC）、5-羟甲基胞嘧啶（5-hydroxycytosine, 5-hmC）含量及氧化应激水平）。采用Embryoviewer软件对ICSI来源的胚胎进行形态动力学分析。本研究结果显示，肥胖男性的富集活动精子组分中残留组蛋白水平更高（p