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Porcine seminal plasma (SP) has been shown to contain factors that have a decapacitative or capacitation-inhibiting effect on sperm. The objectives of the present study were to compare the capacitative changes observed in cooled sperm with those seen in sperm after in vitro capacitation and to determine whether SP could prevent these changes. Sperm were subjected to incubation or to slow cooling under noncapacitating or capacitating conditions. The effect of SP on protein tyrosine phosphorylation and the ability of the sperm to undergo an acrosome reaction (AR) were determined. Cooled sperm displayed an increased level of tyrosine phosphorylation and a higher percentage of induced AR sperm compared to incubated sperm. The addition of SP inhibited the number of ARs that occurred during incubation and cooling. These results suggest that cooling of sperm augments the capacitative changes in sperm, and that SP contains a factor(s) that effectively prevents these changes.

Persistent infertility after apparently successful vasectomy reversal is common. One possible etiology is epididymal epithelial dysfunction resulting in improper sperm maturation after vasectomy reversal. The epididymal epithelium secretes a number of proteins that are thought to be required for the maturation of sperm. Ligation of the vas deferens during vasectomy may affect the synthesis of some of these proteins. In the present study, the function of the epididymal epithelium was assessed at early times after vasectomy (1, 4, and 7 days) by measuring the level of mRNA of 4 secreted proteins: Crisp-1, clusterin, osteopontin, and transferrin. In addition, the site of synthesis of these proteins was determined by immunocytochemistry. The results demonstrated that the expression of Crisp-1 and clusterin, representative epididymal secretory proteins, was largely unaffected by vasectomy. However, osteopontin mRNA increased in the vas deferens in response to vasectomy. Immunocytochemical localization of osteopontin suggested that both infiltrating immune cells and deferential luminal epithelium were responsible for this up-regulation. Transferrin expression was viewed as a marker for immune cells at the site of injury. However, both the caput epididymis and deferential epithelia were found to express transferrin, in addition to immune cells. In conclusion, there appear to be only minor changes in expression of genes encoding epididymal secretory proteins acutely after vasectomy, but, not surprisingly, there was evidence of an inflammatory response after vasectomy.

The rat Crisp-1 gene encodes Protein DE (acidic epididymal glycoprotein; AEG), a glycoprotein secreted by the epididymal epithelium that associates with maturing sperm and has been implicated in the process of sperm-egg fusion. Previous characterization of the Crisp-1 messenger RNA in the rat epididymis has demonstrated the presence of 3 splice variants (Klemme et at, 1999). This study was undertaken to determine if expression of the Crisp-1 splice variants in the rat epididymis is region-specific and correlates with the region-specific pattern of synthesis of the D and E forms of the Crisp-1 protein. Expression of each of the splice variants was shown by RNase protection assays to be under the control of androgens, but they are not differentially regulated either within the epididymal segments or along the length of the organ. The reported structure of the mouse Crisp-1 gene does not include an exon that is equivalent to the rat exon 1, suggesting that the rat splice variants cannot exist in the mouse and may be specific to the rat. Furthermore, the mouse transcription start site is situated in a different region of the gene than in the rat. In this study, a comparison of the mouse and rat genes in the region flanking the mouse exon 1 and the rat exon 2 (within the rat intron 1) shows greater than 80% sequence identity, including the conservation of several putative androgen receptor binding sites. In addition, the rat gene is shown to have a corrupted TATA box in intron 1 that corresponds to the TATA box located in the mouse gene. These observations explain the preferential transcription for the mouse gene in this region, while the predominant start site for the rat gene is 5' of the upstream exon 1. Although an exon corresponding to the rat exon 1 has not been found in the mouse gene, reverse transcription-polymerase chain reaction experiments using mouse epididymal RNA suggest that such an exon exists in the mouse gene and is transcribed at low frequency.