Sperm Ubiquitination Correlation With Human Semen Quality

Background: ubiquitin, an 8.5 kda peptide that marks other proteins for proteasomal degradation, tags defective sperm duringepididymal passage. thus, sperm ubiquitination is a universal marker for sperm defects and can be used as a sperm functiontest. the objective of the present study was to examine the relationships between sperm ubiquitination and clinical semenparameters, using simplified immunofluorescence assays in order to establish ubiquitin as a biomarker of male infertility.methods: semen samples from 100 couples attending avicenna infertility clinic, tehran, iran, were collected and analyzedaccording to who criteria. each sample was washed and adjusted at 106 sperm/ml concentration. sperm were coated onslides, using cytospin centrifugation and were fixed in buffered formaldehyde. subsequently ubiquitinated spermatozoawere evaluated by direct immunofluorescence microscopy using fitc-labeled anti-ubiquitin antibodies. after counting at least 200 sperm per sample, while employing light microscopy, the percentage of biquitinated spermatozoa was recorded on the same fields through epifluorescence microscopy. results: negative correlations were obtained between sperm ubiquitination and sperm count (r=-0.278, p< 0.001), spermconcentration (r=-0.37, p< 0.001), viability (r=-0.407, p< 0.001), sperm morphology (r=-0.509, p< 0.001), rapid progressive motility (a) (r=-0.246, p< 0.001) and slow progressive motility (b) (r=-0.474, p< 0.001). there was a positive correlation between ubiquitinated sperm and the percentage of immotile spermatozoa (r=0.486, p< 0.000). conclusion: increased sperm ubiquitination is inversely associated with good semen quality parameters, supporting the use of ubiquitin as a biomarker for evaluation of human sperm quality.