PDF(Pubmed)
Abstract：
Cryopreservation of sperm is an essential technique in assisted reproduction in cattle. The objective of the study was to systematically review and synthesize the literature on bull semen quality evaluation based on the comparison of morphological and metabolic parameters of cryopreserved bovine spermatozoa such as DNA integrity, mitochondrial status, plasma membrane alterations, total motility, and morphology (% of abnormal cells). The electronic databases PubMed, Web of Sciences, Scopus, and Google Scholar were searched up to December 2023. Studies and references were included if they reported the following parameters: DNA integrity, mitochondrial status, plasma membrane alterations, total motility, and morphological aberrations (% of abnormal cells) for conventional cryopreserved bovine spermatozoa. After an electronic search, out of 1,526 original studies, only 40 were included in the meta-analysis. Standardized mean differences (SMD) with 95% confidence intervals were estimated for the chosen studies, and a meta-analysis was performed using a random effects model. The tau-squared (tau2) and inconsistency index (I2) quantified heterogeneity among different studies. The regression analysis for the evaluated parameters showed a positive correlation between mitochondrial membrane potential (MMP), total motility, and abnormal morphology and a negative correlation between DNA fragmentation index (DFI) and total motility and MMP. Moreover, subgroup analysis demonstrated similar associations for dairy and non-dairy bull breeds, albeit with lower I2 values. The presence of publication bias was confirmed by Egger\'s test, except for the MMP parameter. A multi-parametric analysis of morphological and metabolic parameters can address the existing limitations of cryopreserved bovine spermatozoa quality assessment. Combining imaging flow cytometry (IFC) with standardization of sperm pre-processing and optimization of the experimental protocols may help to differentiate sperm from cellular debris and cytoplasmic droplets of similar size and alleviate limitations demonstrated by conventional sperm analysis.
摘要：
精子冷冻保存是牛辅助生殖的一项重要技术。本研究的目的是通过对低温保存的牛精子DNA完整性等形态和代谢参数的比较,对公牛精液质量评价方面的文献进行系统综述和综合,线粒体状态，质膜改变，总运动性，和形态（异常细胞的百分比）。电子数据库PubMed，WebofSciences,Scopus,和谷歌学者被搜索到2023年12月。如果他们报告了以下参数，则包括研究和参考文献：DNA完整性，线粒体状态，质膜改变，总运动性，常规冷冻保存的牛精子的形态畸变（异常细胞的百分比）。经过电子搜索，在1,526项原始研究中，仅40例纳入荟萃分析.对所选研究进行了95%置信区间的标准化平均差(SMD)估计，采用随机效应模型进行荟萃分析.tau平方（tau2）和不一致性指数（I2）量化了不同研究之间的异质性。评估参数的回归分析显示，线粒体膜电位（MMP），总运动性，形态异常，DNA片段化指数（DFI）与总运动性和MMP呈负相关。此外，亚组分析显示，乳牛和非乳牛品种的关联相似，尽管I2值较低。发表偏倚的存在通过Egger的测试得到证实，MMP参数除外。形态学和代谢参数的多参数分析可以解决冷冻保存的牛精子质量评估的现有局限性。将成像流式细胞术（IFC）与精子预处理的标准化和实验方案的优化相结合，可能有助于将精子与相似大小的细胞碎片和细胞质液滴区分开来，并减轻常规精子分析所显示的局限性。
