Effects of Astragalus polysaccharide to boar sperm on bisphenol A exposure.

Bisphenol A (BPA) is reported to impair male fertility. The alleviating effect of Astragalus polysaccharide (APS) on sperm oxidative damage caused by BPA exposure was analysed for the first time. In this study, the effect of APS (0.25, 0.5, 0.75, 1 mg/mL) on motility of BPA-exposed sperm, energy metabolism indexes, and antioxidant parameters was evaluated. In addition, the effects of APS supplementation on protein tyrosine phosphorylation of BPA-exposed sperm were assessed. The results showed that the addition of APS (0.5 and 0.75 mg/mL) significantly increased motility of BPA-exposed sperm by decreasing the content of malondialdehyde and improving activities of superoxide dismutase and catalase (p < .05). Administration of different doses of APS to BPA-exposed sperm improved mitochondrial membrane potential and energy production (p < .05). Moreover, APS protected and alleviated tyrosine phosphorylation protein on the principal-pieces of BPA-exposed sperm flagella. In conclusion, supplementation with APS enhanced the antioxidant capacity of BPA-exposed sperm and improved in vitro capacitation, thereby improving the reproductive capacity of sperm exposed to environmental hormones.

Effects of zinc chloride on boar sperm quality during liquid storage at 17°C.

OBJECTIVES: The aim of this study was to evaluate the effects of zinc chloride (ZnCl2 ) at 20, 50, 100, and 200 µg/mL on the quality of seminal plasma-free boar sperm stored at 17°C for 7 days and to explore the underlying mechanisms. METHODS: Boar sperm were collected and incubated in non-capacitation/capacitation medium to analyze sperm quality. RESULTS: In the non-capacitated state, the addition of ZnCl2 at 20 and 50 µg/mL improved the survival rate and plasma membrane integrity of boar sperm (p < 0.05). Compared to the control group, the addition of ZnCl2 significantly increased total antioxidative capacity and CuZn superoxide dismutase activity, while reducing the malondialdehyde content (p < 0.05). ZnCl2 at 100 and 200 µg/mL significantly decreased sperm motility, protein kinase A (PKA) substrate phosphorylation, and tyrosine phosphorylation. These proteins were mainly located on the mid-pieces of the flagellum. The addition of ZnCl2 at 20 and 50 µg/mL conveyed a protective effect to boar sperm stored at 17°C. Furthermore, ZnCl2 at 100 and 200 µg/mL inhibited sperm motility via tyrosine phosphorylation, thus preventing the 'capacitation-like' state. In the capacitated state, there was no change in PKA substrate phosphorylation and tyrosine phosphorylation of the mid-pieces of the flagellum compared to the control groups, indicating that the addition of Zn2+ did not negatively affect capacitation of preserved sperm. CONCLUSIONS: ZnCl2 showed protective capacity to the preservation extender used for boar sperm during the process of 17°C storage, and the optimal concentration of ZnCl2 for the preservation extender was 100 µg/mL.

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Bisphenol A (BPA) is a synthetic estrogen compound, which widely exists in the environment, interferes with mammalian endocrine and affects the function of reproductive system of males. Taking fresh sperm of boar, 17 ℃ preservation boar sperm, and mouse sperm as test materials, we examined the effects of BPA (0, 0.1,1,10,100 µmol∙L-1) on proteins tyrosine phosphorylation in sperm and the molecular mechanism by using wes-tern blot (WB) and immunofluorescence techniques coupled to in vitro culture method. The results showed that low BPA concentration (0.1, 1 µmol∙L-1) markedly accelerated the protein tyrosine phosphorylation of fresh boar capacitated sperm. However, the tyrosine phosphorylation of boar sperm decreased in high BPA concentration (10, 100 µmol∙L-1). The tyrosine phosphorylation of the mouse sperm raised with the increases of BPA concentration. Moreover, BPA affected different kinds of proteins related to tyrosine phosphorylation modification of porcine and mouse sperm capacitation, suggesting that the effect of BPA exposure on mammalian sperm was species-specific. Furthermore, the results of immunofluorescence showed that the effects of BPA on protein tyrosine phosphorylation in sperm mainly occurred in the middle and principal piece of flagellum.

Characterization of miRNA profiles in the mammary tissue of dairy cattle in response to heat stress.

BACKGROUND: MicroRNAs (miRNAs) are a class of small noncoding RNAs that play important roles in the regulation of gene expression. However, the role of miRNAs in bovine mammary gland responses to heat stress is not well understood. RESULTS: In the present study, we performed a deep RNA sequencing analysis to identify miRNAs associated with the heat stress potential of the bovine mammary gland. We identified 27 miRNAs that were differentially expressed significantly between the mammary tissue of Holstein cattle heat stress and normal conditions. Twenty miRNAs had higher expression in the mammary tissue of heat-stressed Holstein cattle. The seven highest differentially expressed candidate miRNAs (bta-miR-21-5p, bta-miR-99a-5p, bta-miR-146b, bta-miR-145, bta-miR-2285 t, bta-miR-133a, and bta-miR-29c) identified by deep RNA sequencing were additionally evaluated by stem-loop qPCR. Enrichment analyses for targeted genes revealed that the major differences between miRNAs expression in the mammary gland of heat-stressed versus control were associated with the regulation of Wnt, TGF-ß, MAPK, Notch, and JAK-STAT. CONCLUSIONS: These data indicated that the differentially expressed miRNAs identified in this study may act as dominant regulators during heat stress. We might reduce heat stress damage of Holstein cows by up-regulating or down-regulating these differentially expressed miRNAs.