Centre for Human Reproduction, IMS & SUM Hospital, Bhubaneswar, Odisha, India.
O & G Department, Centre for Human Reproduction, IMS & SUM Hospital, SOA University, Bhubaneswar, Odisha, India.
Andrology. 2018 Sep;6(5):680-689. doi: 10.1111/andr.12500. Epub 2018 Jun 29.
Condensed sperm chromatin is a prerequisite for natural fertilization. Some reports suggested the prevalence of chromatin condensation defects in teratozoospermia cases with head anomalies; conversely, earlier studies exemplified its occurrence in morphologically normal spermatozoa too. The aim of this study was to compare the condensation defects in correlation with head anomalies among different groups of subfertile males and its impact on the rate of fertilization in assisted reproduction procedures. Ultrastructure analysis of spermatozoa through scanning electron microscopy and atomic force microscopy could facilitate an in-depth evaluation of sperm morphology. Nuclear condensation defects (%) in spermatozoa were analyzed in 666 subjects, and its effect on the rate of fertilization was analyzed in 116 IVF and 90 intracytoplasmic sperm injection cases. There was no correlation of condensation defects with head anomalies (%). Student's t-test showed no significant changes in mean values of condensation defects in abnormal semen samples in comparison with the normal group. Condensation defects were observed in normal spermatozoa too, which was negatively associated with the rate of fertilization in IVF (p < 0.01), but intracytoplasmic sperm injection outcome remained unaffected. Ultrastructure study revealed sperm morphological features in height, amplitude, and three-dimensional views in atomic force microscopy images presenting surface topography, roughness property of head, and compact arrangement of mitochondria over axoneme with height profile at nanoscale. In pathological forms, surface roughness and nuclear thickness were marked higher than the normal spermatozoa. Thus, percentage of normal spermatozoa with condensation defects could be a predictive factor for the rate of fertilization in IVF. From diverse shapes of nucleus in AFM imaging, it could be predicted that defective nuclear shaping might be impeding the activity of some proteins/ biological motors, those regulate the proper Golgi spreading over peri-nuclear theca.
浓缩的精子染色质是自然受精的前提。一些报道表明，头部畸形的畸形精子症病例中存在染色质浓缩缺陷的流行；相反，早期的研究也表明这种情况也发生在形态正常的精子中。本研究旨在比较不同亚不育男性群体中与头部异常相关的浓缩缺陷，并分析其对辅助生殖过程中受精率的影响。通过扫描电子显微镜和原子力显微镜对精子进行超微结构分析，可以对精子形态进行深入评估。在 666 名受试者中分析精子的核浓缩缺陷（%），并在 116 例体外受精和 90 例卵胞浆内单精子注射病例中分析其对受精率的影响。浓缩缺陷与头部异常之间没有相关性（%）。学生 t 检验显示，与正常组相比，异常精液样本中浓缩缺陷的平均值没有显著变化。正常精子中也观察到了浓缩缺陷，这与体外受精（IVF）的受精率呈负相关（p<0.01），但卵胞浆内单精子注射的结果不受影响。超微结构研究显示，原子力显微镜图像中的精子形态特征在高度、幅度和三维视图中呈现出表面形貌、头部粗糙度和线粒体在轴丝上的紧密排列，以及纳米级的高度轮廓。在病理形态中，表面粗糙度和核厚度明显高于正常精子。因此，具有浓缩缺陷的正常精子的百分比可能是体外受精受精率的预测因素。从原子力显微镜成像中的不同形状的核可以预测，核形状的缺陷可能会阻碍某些蛋白质/生物马达的活性，这些蛋白质/生物马达调节着正确的高尔基在核周被膜上的扩散。
