Abstract:
Spermatogenesis and testis development are highly structured physiological processes responsible for post-pubertal fertility in stallions. Spermatogenesis comprises spermatocytogenesis, meiosis, and spermiogenesis. Although germ cell degeneration is a continuous process, its effects are more pronounced during spermatocytogenesis and meiosis. The productivity and efficiency of spermatogenesis are directly linked to pubertal development, degenerated germ cell populations, aging, nutrition, and season of the year in stallions. The multiplex interplay of germ cells with somatic cells, endocrine and paracrine factors, growth factors, and signaling molecules contributes to the regulation of spermatogenesis. A cell-to-cell communication within the testes of these factors is a fundamental requirement of normal spermatogenesis. A noteworthy development has been made recently on discovering the effects of different somatic cells including Leydig, Sertoli, and peritubular myoid cells on manipulation the fate of spermatogonial stem cells. In this review, we discuss the self-renewal, differentiation, and apoptotic roles of somatic cells and the relationship between somatic and germ cells during normal spermatogenesis. We also summarize the roles of different growth factors, their paracrine/endocrine/autocrine pathways, and the different cytokines associated with spermatogenesis. Furthermore, we highlight important matters for further studies on the regulation of spermatogenesis. This review presents an insight into the mechanism of spermatogenesis, and helpful in developing better understanding of the functions of somatic cells, particularly in stallions and would offer new research goals for developing curative techniques to address infertility/subfertility in stallions.
摘要:
精子发生和睾丸发育是导致种马青春期后生育的高度结构化的生理过程。精子发生包括精母细胞发生,减数分裂,和精子生成。尽管生殖细胞变性是一个连续的过程,在精子细胞发生和减数分裂期间,其作用更为明显。精子发生的生产力和效率与青春期发育直接相关,退化的生殖细胞群,老化,营养,和种马一年中的季节。生殖细胞与体细胞的多重相互作用,内分泌和旁分泌因子,生长因子,和信号分子有助于精子发生的调节。这些因子在睾丸内的细胞间通讯是正常精子发生的基本要求。最近在发现包括Leydig在内的不同体细胞的影响方面取得了值得注意的进展,Sertoli,和管周肌样细胞对精原干细胞命运的操纵。在这次审查中,我们讨论自我更新,分化,正常精子发生过程中体细胞的凋亡作用以及体细胞与生殖细胞之间的关系。我们还总结了不同增长因素的作用,它们的旁分泌/内分泌/自分泌途径,以及与精子发生相关的不同细胞因子。此外,我们强调了进一步研究精子发生调节的重要事项。这篇综述介绍了精子发生的机制,有助于更好地理解体细胞的功能,特别是在种马中,并将为开发治疗技术以解决种马的不育症/不育症提供新的研究目标。