Increase in fluid viscosity during epididymal transit and the immobilization of rat epididymal spermatozoa

Safety assessment of cefuroxime on male reproductive system: Subacute toxicity and potential reversibility after a complete cycle of spermatogenesis and epididymal maturation in Wistar rats

The effects of cefuroxime on reproductive system were investigated in male rats. Doses of 0, 30, 60 or 120 mg/kg of cefuroxime were intraperitoneally injected daily, for 7 days. Half of the rats were euthanized 24 h after the last dose and other half were induced to death 70 days after the last treatment. After 8 days of the experiment, results showed that cefuroxime induced a significant reduction in the weights of testes, epididymis and accessory sex organs. In addition, it decreased sperm quality, plasma testosterone level, and antioxidant enzyme activities while increasing the level of malondialdehyde. After a complete cycle of spermatogenesis and epididymal maturation, the results indicated complete reversibility of the adverse effects previously mentioned. In conclusion, cefuroxime induced reversible dose-dependent adverse effects on testicular and epididymal functions of rats.

Maturation of sperm volume regulation in the rat epididymis

Sperm maturation in the epididymis may involve differences between mature and immature spermatozoa in their volume regulatory osmolyte response. Spermatozoa obtained from the rat caput and cauda epididymidis were examined for their ability to regulate volume after transfer from in situ epididymal osmolality (measured to be 343 +/- 13 and 365 +/- 19 mmol kg(-1), respectively) to that of the female tract in single- and multiple-step protocols. Cells withstood the single-step treatment better than the multistep protocol. Sperm volume estimates by flow cytometric measurements of forward scatter of cells with intact head membranes was more sensitive than those by assessing cell coiling microscopically. At osmolalites below 210 mmol kg(-1) both caput and cauda cells ruptured, limiting the use of flow cytometry. Above this critical value, the use of quinine showed that both caput and cauda cells could regulate volume, but cauda cells were the more effective. Of several organic osmolytes studied, myo-inositol, glutamate and KCl caused only temporary and slight swelling of spermatozoa cells in hypotonic medium. Spermatozoa of both maturities seemed to use potassium as the preferred osmolyte for regulating volume.

Secretory proteins from the epididymis and their clinical relevance

The literature pertaining to epididymal proteins and their functions in fertilization is reviewed. Animal studies have indicated that specific epididymal proteins may be involved in aspects of sperm motility, sperm-zona binding and the acrosome reaction. If analogous proteins in the human exist, use could be made of them in the andrology clinic. Currently, only one specific epididymal protein (alpha-glucosidase) is routinely measured for semen analysis. Glucosidase secretion, in addition to reflecting inflammation of the organ, is used in conjunction with other markers of human fertility to identify patients with ductal occlusion for whom bypass operations may be useful therapy. Glucosidase inhibitors have been used to improve the assay, by establishing true semen blank values, and to quantify histochemical activity in frozen tissue sections. From its localization in the human corpus and cauda epididymidis, neutral glucosidase can not be used to identify occlusion in the proximal regions of the duct. Other proteins may be valuable markers of these regions. In the future, other specific proteins of epididymal origin found in seminal fluid could well illuminate dysfunction of the organ in cases of infertility or be end-points of the disruptive action of drugs aimed at the epididymis.

The effect of viscosity of semen diluents on motility of bull spermatozoa

The effect of egg yolk extender on semen viscosity and bull sperm motility of fresh and cooled or deep frozen semen was determined by a computer-assisted system. Viscosity of the extender was determined by flow time. Based on the sperm velocity (velocity of the average path), individual spermatozoon were classified into groups of progressively motile (>==30 microm/sec) and immotile (<10 microm/sec) spermatozoa. The average velocity of progressively motile spermatozoa (VPM), the velocity of linear progressively motile spermatozoa (VLP) and the percentage of linear swimming spermatozoa (LIN) were evaluated. The addition of 10, 20 or 30% egg yolk to Tris buffer (pH 6.5) resulted in a linear decrease of VPM and a decrease in the percentage of progressively motile spermatozoa, but it increased the relative rate of LIN in fresh diluted semen. Increasing the levels of egg yolk in the diluent resulted in higher viscosity. The VLP was significantly higher than the VPM. In refrigerated or frozen semen samples, extender with 30 and 20% egg yolk had a similar effect on the VPM but not on the percentage of progressively motile sperm cells. Freezing of egg yolk (30%) extender to -20 degrees C resulted in a significant increased flow time and higher viscosity. Dilution of semen samples with high viscosity extender decreased the VPM in fresh and chilled semen. Freezing semen of high viscosity extender with glycerol had no apparent effect on the percentage of progressively motile spermatozoa compared with that of non-glycerinated egg yolk extender. The results suggest that different concentrations of egg yolk in the extender can influence the parameters of semen viscosity and sperm motility evaluated by a computer-assisted system.

Pre- and peri-ovulatory distribution of viable spermatozoa in the pig oviduct: a scanning electron microscope study

Using sexually mature animals, the distribution of spermatozoa has been examined at the utero-tubal junction and in the distal and proximal portions of the oviduct isthmus. Mating occurred during early oestrus and, with one exception, specimens were prepared shortly before or after ovulation. Distinct reservoirs of spermatozoa were identified in furrows between the terminal folds of the isthmus, and particularly within the troughs and transverse ridges of this region. The density of spermatozoa diminished steeply from the utero-tubal junction towards the isthmus, especially in the pre-ovulatory specimens. The membranes of most spermatozoa in the isthmus were intact up to the time of ovulation, suggesting that the acrosome reaction is a peri- or post-ovulatory event. Whilst the flagella of spermatozoa in the reservoirs were usually straight or only slightly curved, those on the surface of the epithelial folds were undulating (S-shaped). Specific microenvironments may therefore exist in the distal portion of the isthmus to regulate sperm motility; droplets of secretion were a notable feature in this region. In specimens prepared 24 hr after ovulation, spermatozoa were almost absent from the utero-tubal junction and isthmus. However, denuded eggs were observed in the proximal portion of the isthmus in this animal, and they had spermatozoa associated with the zona pellucida. Arguments are presented for a peri-ovulatory endocrine regulation of sperm redistribution and capacitation.