Proteomic approaches have been widely used in reproductive studies to uncover protein biomarkers of bull fertility. Seminal plasma is one of the most relevant sources of these proteins that may influence sperm physiology. Nonetheless, there are still gaps in existing knowledge in the functional attributes of seminal proteins. Thus, we reviewed the relationships between seminal plasma proteins and bull fertility by conducting a systematic review with data obtained from 71 studies. This review showed that the associations between fertility improvement with the use of total seminal plasma proteins are still controversial. None of the studies explored the sperm fertilizing ability following these interactions. By contrast, the exposure to a single protein, such as osteopontin, binder of sperm proteins, and heparin binding proteins, can increment sperm motility, capacitation, and fertilizing ability by modulating intracellular calcium concentrations, removing lipids from sperm membranes, and regulating the acrosome reaction. Variations in protein analyses and the protein contents and their abundances between animals contributed to the difficulty of establishing protein biomarkers of fertilizing potential of the bull sperm. Indeed, the heterogenicity of methodologies was a limitation of this review. Standardized methods of seminal protein analyses, as well as sperm endpoints, may minimize such discrepancies. In conclusion, potential biomarkers of sperm parameters are still to be established. Future studies should evaluate protein isoforms and how they interact with sperm to ascertain their biological functions.
Pulmonary arterial hypertension (PAH) is characterized by elevated arterial pressure and vascular resistance. PAH may cause alterations in the microcirculation of several organs, including the kidney, liver, brain, and testes. However, it remains unclear whether monocrotaline-induced PAH exerts detrimental effects on animal testes. Thus, we analyzed the impact of PAH on testicular morphology and function. Additionally, we investigated the effect of resistance exercise training (RT) on testicular parameters in PAH rats. Eight healthy Wistar rats and eight PAH rats were subjected to RT training for 30 days; the other PAH and healthy rats (n = 8/group) did not exercise. PAH rats had lower reproductive organ weight, serum testosterone levels, testicular glucose, and nitric oxide (NO) levels, Leydig cell parameters, tubular morphometry, germ cell counts, and daily sperm production than healthy animals did. The practice of RT attenuated the negative impact of PAH on the relative weights of the testes and epididymides, Leydig cell number, nuclear volume, testicular NO levels, and seminiferous epithelium architecture. Moreover, RT positively influenced testosterone levels in PAH animals. We conclude that PAH exerts deleterious effects on testicular histology and function. However, RT can be beneficial to the PAH-affected testicular parameters.
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