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This paper investigates the mechanism of action of heavy ion radiation (HIR) on mouse testes. The testes of male mice subjected to whole body irradiation with carbon ion beam (0.5 and 4Gy) were analyzed at 7days after irradiation. A two-dimensional gel electrophoresis approach was employed to investigate the alteration of protein expression in the testes. Spot detection and matching were performed using the PDQuest 8.0 software. A difference of more than threefold in protein quantity (normalized spot volume) is the standard for detecting differentially expressed protein spots. A total of 11 differentially expressed proteins were found. Protein identification was performed using matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry (MALDI-TOF-TOF). Nine specific proteins were identified by searching the protein sequence database of the National Center for Biotechnology Information. These proteins were found involved in molecular chaperones, metabolic enzymes, oxidative stress, sperm function, and spermatogenic cell proliferation. HIR decreased glutathione activity and increased malondialdehyde content in the testes. Given that Pin1 is related to the cell cycle and that proliferation is affected by spermatogenesis, we analyzed testicular histological changes and Pin1 protein expression through immunoblotting and immunofluorescence. Alterations of multiple pathways may be associated with HIR toxicity to the testes. Our findings are essential for studies on the development, biology, and pathology of mouse testes after HIR in space or radiotherapy., (Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.)

Aims Proteomic analysis of serum biomarkers to determine liver toxicity after exposure to cosmic radiation has not been performed previously. This study was to identify serum biomarkers associated with hepatotoxicity following exposure to iron ion radiation. Main methods Male mice were whole-body irradiated with a 2 grayunit (Gy) iron ion beam, and after 3 months, serum and liver samples were collected. Two-dimensional electrophoresis (2-DE) was used to separate the identified serum proteins, and matrix-assisted laser desorption/ionization tandem mass spectrometry (MALDI-TOF-TOF) was performed to identify differentially expressed proteins. Enzyme-linked immunosorbent assays and immunoblotting were applied to evaluate protein expression, and immunohistochemistry and immunofluorescence were used to investigate protein localization. Real-time polymerase chain reaction (PCR) was performed to confirm altered gene expression. Key findings A total of 11 spots that showed differential expression were screened and identified as seven proteins. Of these, six proteins were in the same bioinformatics network and included complement component 3, serum amyloid P-component, apolipoprotein E, alpha-2-macroglobulin, fibrinogen alpha chain, and fibrinogen gamma chain. All of these proteins are synthesized by the liver, and may play an important role in liver toxicity. We also confirmed the mRNA transcription, and found that mRNA expression of the six identified proteins increased in the liver in irradiated mice. Significance These results suggest that these proteins may be potential biomarkers of hepatotoxicity in astronauts enduring long space missions. [ABSTRACT FROM AUTHOR]

The toxicological mechanism of low sperm motility induced by iron ion radiation (IIR) was investigated in mice. Reproductive organ indices were measured following whole-body irradiation with a 2 Gy iron ion beam. Two-dimensional gel electrophoresis, immunoblotting and immunofluorescence were used to analyze protein expression, and real-time polymerase chain reaction was performed to confirm altered gene expression. Reproductive organ indices and sperm motility were lowest 2 weeks after IIR. Sperm function changes via testis and cauda epididymis function were also determined at this time point. Sixteen differentially expressed proteins were identified in sperm 2 weeks after IIR. Bioinformatics analysis indicated that alpha-enolase (Eno1) may be important in the regulation of glycolysis in sperm, and Eno1 expression was correlated with sperm motility. Eno1 may be a potential marker for low sperm motility induced by IIR, and these results may provide a useful reference for changes in astronaut fertility during long space missions. [ABSTRACT FROM AUTHOR]

In this study proteomics analysis was performed to investigate damage caused to ram sperm by the freeze-thaw process. Sperm motility, viability, reactive oxygen species (ROS) and adenosine triphosphate (ATP) content were measured to evaluate sperm quality. Compared with fresh groups, motility, viability and ATP content were all lower in freeze–thawed sperm (P < 0.001), and ROS content was higher (P < 0.001). Moreover, 25 differential protein spots were detected in two-dimensional gels using PDQuest 8.0 software and the corresponding proteins were identified using matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry (MALDI-TOF-TOF MS) coupled with searching of the NCBI protein sequence database. Among these proteins, hexokinase1 (HXK1), the enzyme that catalyzes the first step of glycolysis in the sperm glycolytic pathway, is known to be associated with sperm motility. Casein kinase II subunit alpha (CSNK2A2), a serine/threonine-selective protein kinase, is associated with sperm apoptosis. We used immunoblotting and immunofluorescence to analyze the expression and localization of these two proteins. HXK1 and CSNK2A2 expression levels in fresh sperm were significantly higher than that in freeze-thawed sperm (P < 0.001). HXK1 and CSNK2A2 were detected in the main part of the sperm flagellum, and the immunofluorescence signal from these proteins was weakened in the freeze-thawed group. Decreased expression of HXK1 and CSNK2A2 may be associated with decreased sperm motility and viability following freeze-thawing. [ABSTRACT FROM AUTHOR]

Highlights: [•] Proteomics of pubertal mice testes after carbon ion radiation were examined. [•] Differential proteins in 2-DE gels were investigated 14 days after irradiation. [•] Eight proteins were identified among the differentially expressed protein spots. [•] The relationship between mRNA and the abundance of proteins were confirmed. [•] These proteins may lead to new insights into the information of CIR toxicity. [Copyright &y& Elsevier]