Parrish John J, Willenburg Kilby L, Gibbs Katelynn M, Yagoda Kylie B, Krautkramer Megan M, Loether Teyanna M, Melo Fabiana C S A
Department of Animal Sciences, University of Wisconsin-Madison, Madison, Wisconsin.
Department of Animal Biology, Federal University of Viçosa, Viçosa, Brazil.
Mol Reprod Dev. 2017 Sep;84(9):969-978. doi: 10.1002/mrd.22841. Epub 2017 Jul 11.
Seasonal infertility is a limiting factor in boar fertility, and is increasingly important as climate changes. Spermatogenesis in the boar produces 256 spermatozoa per type A spermatogonium, but the process is inefficient such that only 10-30% of these potential spermatozoa are actually produced. Heat further impacts spermatogenesis by reducing the number of specific germ cells produced while increasing the fraction of abnormal sperm. Early studies used whole-animal exposure to simulate seasonal exposure to heat under production settings, but this approach is associated with many confounding factors that make assessment of the mechanisms of heat-induced damage to spermatogenesis difficult. Scrotal insulation provides a better model to investigate the mechanisms and potential mitigation strategies of heat-induce damage. For example, scrotal insulation helped identify a link between short-term heat stress and damage to meiotic germ cells. This outcome is likely due to changes in the integrity of the blood-testis barrier, which induce apoptosis, autophagy and DNA damage in the germ cells. Further understanding how heat damages spermatogenesis, and whether or not this can be repaired, are crucial to mitigating heat effects on boars in production settings.
季节性不育是公猪繁殖力的一个限制因素，并且随着气候变化其重要性日益增加。公猪的精子发生过程中，每个A型精原细胞可产生256个精子，但该过程效率低下，实际上只能产生这些潜在精子的10%-30%。高温会进一步影响精子发生，减少特定生殖细胞的数量，同时增加异常精子的比例。早期研究通过让动物整体暴露在环境中，模拟生产环境下季节性高温暴露，但这种方法存在许多混杂因素，使得评估高温诱导精子发生损伤的机制变得困难。阴囊隔热提供了一个更好的模型来研究高温诱导损伤的机制和潜在的缓解策略。例如，阴囊隔热有助于确定短期热应激与减数分裂生殖细胞损伤之间的联系。这一结果可能是由于血睾屏障完整性的改变，从而诱导生殖细胞发生凋亡、自噬和DNA损伤。进一步了解高温如何损害精子发生以及这种损害是否可以修复，对于减轻生产环境中高温对公猪的影响至关重要。
