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ANALYSIS OR THE POTENTIAL SPERM BIOMARKER, SP22, IN HUMAN SEMEN
Citation:
Morris, R A., G R. Klinefelter, N L. Roberts, J D. Suarez, L F. Strader, S C. Jeffay, AND S P. Darney. ANALYSIS OR THE POTENTIAL SPERM BIOMARKER, SP22, IN HUMAN SEMEN. Presented at Society for the Study of Reproduction, Cincinnati, OH, July 19-22, 2003.
Description:
ANALYSIS OF THE POTENTIAL SPERM BIOMARKER SP22 IN HUMAN SEMEN
Rebecca A. Morris Ph.D.1, Gary R. Klinefelter Ph.D.1, Naomi L. Roberts 1, Juan D. Suarez 1,
Lillian F. Strader 1, Susan C. Jeffay 1 and Sally D. Perreault Ph.D.1
1 U.S. EPA / ORD / National Health and Environmental Effects Research Laboratory /
Reproductive Toxicology Division / Gamete and Early Embryo Biology Branch Research Triangle
Park NC
Sperm proteins associated with fertilizing ability could serve as biomarkers for detection of chemically-induced changes in semen quality and sperm function. One such protein, SP22, is diminished after exposure to epididymal and testicular toxicants in rats, and this diminution is highly correlated with reductions in fertility. These qualities suggest that SP22 may be useful as a biomarker of adverse effects and an indicator of sperm function in humans. Several epidemiological and clinical studies are attempting to utilize home semen collection kits that allow men to collect a sample at their convenience and send it via overnight mail to the laboratory. However, it is possible that overnight storage may affect the amounts of SP22 protein localized within the sperm membrane. Here we test whether SP22 protein levels remain constant after overnight storage, to determine if reliable quantification of SP22 can be conducted after the semen sample has been shipped overnight from a remote location. Semen from each of six men enrolled in an ongoing epidemiology study was divided to analyze one aliquot immediately after liquefaction (Day 1) and the other after storage overnight at room temperature (Day 2). After filtration through nylon mesh, sperm were washed, recounted and then detergent extracted. Proteins were resolved by 2-D PAGE followed by silver staining, and SP22 was quantified from gels with either equally-loaded sperm number (5 million) or equally-loaded protein amount (30 ug). Identity of SP22 spots was confirmed on immunoblots using an antibody to recombinant SP22. Integrated Optical Density (I.O.D) for SP22 did not differ significantly by loading parameter. Furthermore, values for Day 2 samples did not differ consistently from Day 1, suggesting that it may be feasible to measure SP22 in shipped semen samples. However, more data are being generated to confirm this assertion since our sample size was limited. This study lays the groundwork for the feasibility of monitoring SP22 in epidemiology studies. (This abstract of a proposed presentation does not necessarily reflect EPA policy).
Keywords
human sperm, sp22, biomarker, fertility