Fig 1: Comparisons of differentially expressed proteins and two protein modifications between EXP and CON groups. EXP: The experimental group with sperm DNA fragmentation index (DFI) ≥ 30%; CON: The control group with sperm DFI < 30%; n = 2 for each group. A Western blot showed that the expression levels of RAD23B and DFFA in the experimental group were significantly higher than those in the control group, which were consistent with the results of proteomic analysis. B Sperm proteins were separated by 12% of polyacrylamide gel electrophoresis and stained by Coomassie brilliant blue, and there was no obvious changes in sperm protein levels between the experimental group and control group. C Sperm proteins were separated by 12% of polyacrylamide gel electrophoresis and detected with antibodies against ubiquitins, and the results showed that the ubiquitination modification of sperm proteins at approximately 100 kD in the experimental group was significantly higher than that in the control group. D Sperm proteins were separated by 12% of polyacrylamide gel electrophoresis and detected with antibodies against acetyllysine, and the results showed that the acetylation modification of sperm proteins at 20–45 kD in the experimental group was significantly higher than that in the control group