Effect of Pseudomonas aeruginosa on sperm capacitation and protein phosphorylation of boar spermatozoa

Several studies have reported the detrimental effects that bacteriospermia causes on boar sperm quality, but little is known about its effects on IVC. Considering that, the present study sought to evaluate the effects of different concentrations of Pseudomonas aeruginosa on different indicators of capacitation status (sperm viability, membrane lipid disorder, sperm motility kinematics, and protein phosphorylation of boar spermatozoa) after IVC. Flow cytometry and computer assisted sperm analysis (CASA) revealed that the presence of P aeruginosa in boar sperm samples, mostly at concentrations greater than 106 CFU/mL, is associated with a significant (P < 0.05) decrease in the percentages of both sperm membrane integrity and sperm with low membrane lipid disorder, and also with a reduction in sperm motility kinetic parameters when compared with results obtained from the control sample, which presented the typical motility pattern of capacitated-like boar spermatozoa. Moreover, Western blot results also showed significant (P < 0.05) changes in the levels of tyrosine, serine, and threonine protein phosphorylation because of bacterial contamination, the decrease in phosphotyrosine levels of p32, a well-known marker of IVC achievement in boar sperm, being the most relevant. Indeed, after 3 hours of IVC, phosphotyrosine levels of p32 in the control sample were 3.13 ± 0.81, whereas in the tubes with 106 and 108 CFU/mL were 1.05 ± 0.20 and 0.36 ± 0.07, respectively. Therefore, the present study provides novel data regarding the effects of bacterial contamination on boar sperm, suggesting that the presence of P aeruginosa affects the fertilizing ability of boar sperm by altering its ability to accomplish IVC.