The effects of vaginal lubricants on sperm function: an in vitro analysis.

BACKGROUND: Despite being marketed as "sperm friendly", some vaginal lubricants are known to be detrimental to sperm function and therefore could negatively affect fertility. Many others have not yet been assessed in regards to their effect on sperm function. This issue may concern couples trying to conceive both naturally and via artificial reproductive technologies (ART). AIM: The aim of this research was to analyse the effects that lubricants, commonly used in the setting of natural conception and ART, have on sperm function in an in vitro setting. This was done by assessing sperm motility, vitality and DNA fragmentation following treatment with commercial lubricants or control preparations. We have attempted to mimic the conditions of the vaginal environment in our clinical trial, and so have compiled a list of lubricants that are likely to have minimal negative effect on sperm function in vivo or are "sperm friendly". METHODS: Ten samples were obtained for the study from patients attending a fertility clinic. Once collected, the sperm samples were prepared by density gradient centrifugation and incubated with 11 different lubricants including positive and negative controls for 30 min at 37 °C to mimic the temperature inside the female reproductive tract. Sperm motility, vitality and DNA fragmentation were assessed to determine the effects of the lubricants on sperm function and DNA integrity. RESULTS: Nine lubricants were investigated including Sylk™, Conceive Plus®, glycerol, Johnson's® Baby Oil, SAGE® Culture Oil, Yes®, Forelife™, MaybeBaby® and Pre-seed®. The lubricant which had the best results in terms of vitality, at 92%, was Pre-seed® and the worst was Forelife™ with 28% vitality. In terms of motility, Pre-seed® resulted in the highest percentage of spermatozoa with progressive motility at 86% and Sylk™ resulted in the lowest percentage of progressively motile cells in the sample with 31% of sperm progressively motile. There were no significant effects on DNA integrity. CONCLUSIONS: Pre-seed® was the lubricant which had the least negative effect on sperm function, with Conceive Plus® a close second, due to the significantly higher sperm motility and vitality parameters measured following lubricant exposure.

The distribution and expression of CFTR restricts electrogenic anion secretion to the ileum of the brushtail possum, Trichosurus vulpecula.

In eutherian mammals, fluid secretion is essential for intestinal function. This is driven by electrogenic Cl(-) secretion, which involves a NaK2Cl cotransporter (NKCC1) in the enterocyte basolateral membrane and the cystic fibrosis transmembrane conductance regulator (CFTR) in the apical membrane. However, in the possum ileum, NKCC1 expression is low and secretagogues stimulate electrogenic HCO(3)(-) secretion driven by a basolateral NaHCO(3) cotransporter (pNBCe1). Here we investigated whether electrogenic anion secretion occurs in possum duodenum and jejunum and determined the role of CFTR in possum intestinal anion secretion. Prostaglandin E(2) (PGE(2)) and forskolin stimulated a large increase in ileal short-circuit current (I(sc)), consistent with electrogenic HCO(3)(-) secretion, but had little effect on the duodenal and jejunal I(sc). Furthermore, 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB) and N-(2-naphthalenyl)-[(3,5-dibromo-2,4-dihydroxyphenyl)methylene]glycine hydrazide (GlyH101) inhibited cloned possum CFTR in cultured cells and the PGE(2)-stimulated ileal I(sc), implicating CFTR in ileal HCO(3)(-) secretion. Consistent with this, CFTR is expressed in the apical membrane of ileal crypt and lower villous cells, which also express pNBCe1 in the basolateral membrane. In contrast, duodenal and jejunal CFTR expression is low relative to the ileum. Jejunal pNBCe1 expression is also low, whereas duodenal and ileal pNBCe1 expression are comparable. All regions have low NKCC1 expression. These results indicate that cAMP-dependent electrogenic Cl(-) secretion does not occur in the possum small intestine because of the absence of CFTR and NKCC1. Furthermore, CFTR functions as the apical anion conductance associated with HCO(3)(-) secretion and its distribution limits electrogenic HCO(3)(-) secretion to the ileum.

Electrogenic Cl(-) secretion does not occur in the ileum of the Australian common brushtail possum, Trichosurus vulpecula, due to low levels of expression of the NaK2Cl cotransporter, NKCC1.

The colon of the brushtail possum does not have an electrogenic secretory response. Given the functional significance of electrogenic Cl(-) secretion in the intestine of eutherian mammals, we have investigated the secretory response in the small intestine of this marsupial. In the Ussing chamber cAMP-dependent secretagogues stimulated a sustained increase in ileal short-circuit current (Isc), whereas Ca(2+)-dependent secretagogues induced a transient increase. Both the responses were inhibited by mucosal addition of the anion channel blocker 5-nitro-2-(3-phenylpropylamino) benzoic acid (100 mciromol l(-1)), consistent with an anion secretory response. However, the responses were not inhibited by serosal bumetanide (10 mciromol l(-1)) and were independent of bath Cl(-), indicating that the stimulated ileal Isc does not involve electrogenic Cl(-) secretion driven by the NaK2Cl cotransporter, NKCC1. Consistent with this, there were low levels of NKCC1 expression in the ileal epithelium. In particular, NKCC1 expression in the ileal crypt cells was comparable to that of the villous cells. This differs from eutherian mammals where high levels of NKCC1 expression in the ileal crypt cells are associated with their role in Cl(-) secretion. The cAMP- and Ca(2+)-dependent secretory responses were inhibited by the removal of HCO(3) (-) suggesting that these responses were due to electrogenic HCO(3) (-) secretion. We conclude that the ileum of the possum does not secrete Cl(-) due to low levels of NKCC1 expression. It does however appear to secrete HCO(3) (-). These results are further significant examples of differences in the transport function of the possum intestinal epithelium compared with eutherian mammals.