Project description:Current human reproductive risk assessment methods rely on semen and serum hormone analyses, which are not easily comparable to the histopathological endpoints and mating studies used in animal testing. Because of these limitations, there is a need to develop universal evaluations that reliably reflect male reproductive function. We hypothesized that toxicant-induced testicular injury can be detected in sperm using mRNA transcripts as indicators of insult. To test this, we exposed adult male Fischer 344 rats to low doses of model testicular toxicants and classically characterized the testicular injury while simultaneously evaluating sperm mRNA transcripts from the same animals. Overall, this study aimed to: 1) identify sperm transcripts altered after exposure to the model testicular toxicant, 2,5-hexanedione (HD) using microarrays; 2) expand on the HD-induced transcript changes in a comprehensive time course experiment using qRT-PCR arrays; and 3) test these injury indicators after exposure to another model testicular toxicant, carbendazim (CBZ). Microarray analysis of HD-treated adult Fischer 344 rats identified 128 altered sperm mRNA transcripts when compared to control using linear models of microarray analysis (q < 0.05). All transcript alterations disappeared after 3 months of post-exposure recovery. In the time course experiment, time-dependent alterations were observed for 12 candidate transcripts selected from the microarray data based upon fold change and biological relevance, and 8 of these transcripts remained significantly altered after the 3-month recovery period (p < 0.05). In the last experiment, 8 candidate transcripts changed after exposure to CBZ (p < 0.05). The two testicular toxicants produced distinct molecular signatures with only 4 overlapping transcripts between them, each occurring in opposite directions. Overall, these results suggest that sperm mRNA transcripts are indicators of low dose toxicant-induced testicular injury in the rat. Rats were exposed to sub-chronic low doses of the Sertoli cell toxicant 2,5-hexanedione (HD) or water (control for HD) for 3 months. Some rats in each group underwent 3 months of post-exposure recovery.

Project description:Current human reproductive risk assessment methods rely on semen and serum hormone analyses, which are not easily comparable to the histopathological endpoints and mating studies used in animal testing. Because of these limitations, there is a need to develop universal evaluations that reliably reflect male reproductive function. We hypothesized that toxicant-induced testicular injury can be detected in sperm using mRNA transcripts as indicators of insult. To test this, we exposed adult male Fischer 344 rats to low doses of model testicular toxicants and classically characterized the testicular injury while simultaneously evaluating sperm mRNA transcripts from the same animals. Overall, this study aimed to: 1) identify sperm transcripts altered after exposure to the model testicular toxicant, 2,5-hexanedione (HD) using microarrays; 2) expand on the HD-induced transcript changes in a comprehensive time course experiment using qRT-PCR arrays; and 3) test these injury indicators after exposure to another model testicular toxicant, carbendazim (CBZ). Microarray analysis of HD-treated adult Fischer 344 rats identified 128 altered sperm mRNA transcripts when compared to control using linear models of microarray analysis (q < 0.05). All transcript alterations disappeared after 3 months of post-exposure recovery. In the time course experiment, time-dependent alterations were observed for 12 candidate transcripts selected from the microarray data based upon fold change and biological relevance, and 8 of these transcripts remained significantly altered after the 3-month recovery period (p < 0.05). In the last experiment, 8 candidate transcripts changed after exposure to CBZ (p < 0.05). The two testicular toxicants produced distinct molecular signatures with only 4 overlapping transcripts between them, each occurring in opposite directions. Overall, these results suggest that sperm mRNA transcripts are indicators of low dose toxicant-induced testicular injury in the rat.

Project description:Infertility is a widespread problem, affecting around 15% of couples worldwide, and is defined as the inability to achieve pregnancy within one year despite unprotected intercourse 1. Infertility can be caused by either male or female reproductive issues. Various medical conditions including malignancies, infections, urogenital conditions, or genetic causes can contribute to male infertility. However, 30-40% of men in their reproductive age are affected by idiopathic infertility, according to the guidelines of European Association of Urology (EAU) 1. Towards a better understanding of male infertility, it is mandatory to achieve a comprehensive understanding of involved genes, their RNA transcripts, and regulatory factors, including miRNAs, which influence the expression level of proteins. Therefore, such proteins need to be identified to investigate their role in spermatogenesis and male infertility. Although there are numerous studies on RNAs, including miRNAs related to male infertility 2-9, there are few studies aiming to cover the whole proteome of human sperm 10. The sperm transcriptome comprises a total of 60,505 transcripts including 11,688 differentially expressed transcripts in infertile and fertile men, as reported by Joshi et al. (2022)11. The entire sperm proteome encompasses 6871 proteins, as summarized by Castillo et al. (2018)10. Nevertheless, there is still a lack of high-throughput studies aiming to identify dysregulated proteins in sperm from subfertile men. Only few studies focused on comparisons of the sperm proteome in men with asthenozoospermia and there is virtually no proteomic studies of oligoasthenozoospermic men 12. Some identified proteins in sperm have functions in maintaining sperm motility and enabling fertilization and are involved in structural composition and/or energy metabolism 12-14 and others are not yet functionally characterized. In this study, we employed Mass spectrometry (MS) technology that is still rarely used in the field of human reproductive research to investigate the proteomic landscape of human sperm and their differential expression patterns in men with subfertility.

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A comparative profile of the mRNA and microRNA transcriptome in immature and mature bovine testes

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