Evaluation of the hypo-osmotic swelling test in relation with advanced methods of semen analysis

Isolation and characterization of heparin and gelatin binding buffalo seminal plasma proteins and their effect on cauda epididymal spermatozoa

Seventy semen ejaculates were obtained from 14 Murrah buffalo bulls and were subjected to plasma separation immediately after collection by centrifugation at 2000 rpm for 20 min and stored in liquid nitrogen until analysis. In the seminal plasma the total protein concentration were estimated and the heparin and gelatin binding (HB and GB) proteins were isolated using heparin and gelatin affinity column chromatography. The molecular weight of individual isolated HB and GB protein was determined by SDS-PAGE analysis. Buffalo bull spermatozoa was collected from cauda epididymis under aseptic conditions and was used for the in vitro fertility tests (i.e. bovine cervical mucus penetration test (BCMPT) and hypo-osmotic swelling test (HOST)). The heparin and gelatin binding buffalo seminal plasma proteins were used in six concentrations i.e. 10, 20, 30, 40, 50 and 60 microg/ml to test their effect on in vitro fertility assessment of cauda epididymal spermatozoa. The overall mean values of total protein, HB and GB proteins were recorded as 29+/-2.7, 2.61 and 0.2mg/ml, respectively. Eighteen total protein bands were observed in the range of 12-127 kDa. Eight major HB proteins were isolated in the range of 13-71 kDa. Seven major GB proteins were isolated in the range of 13-61 kDa in the buffalo seminal plasma. The mean penetration distance (mm) travelled by the buffalo cauda spermatozoa was maximum in HB proteins (26.9+/-0.6) followed by GB proteins (25.4+/-0.6) and control (21.2+/-1.4). The difference in BCMPT values between protein treated and control group was significant (P<0.05). Almost similar trend in the effect of protein on values of HOST percentage in both HB and GB proteins treated semen samples were recorded (66.4+/-0.65 and 66.1+/-0.6, respectively). The difference in HOST values between proteins treated and control group (50.4+/-2.0) was significant (P<0.05). The present results indicate that among the isolated proteins, 4 proteins were commonly seen in both the heparin and gelatin-sepharose affinity column chromatography, and the addition of buffalo seminal plasma proteins improved the in vitro sperm functions (40 microg/ml gave best results) of buffalo cauda spermatozoa.

Effect of freeze-thawing procedure on chromatin stability, morphological alteration and membrane integrity of human spermatozoa in fertile and subfertile men

Cryopreservation is known to impair sperm motility and decrease the fertilization rate by detrimental effects on acrosomal structure and acrosin activity. However, the consequences of cryopreservation on the integrity of the sperm nucleus, chromatin stability and centrosome are less clear. The present study was designed to determine the effect of the freeze-thawing procedure on chromatin condensation (aniline blue staining) and the morphology (strict criteria) and membrane integrity of human spermatozoa. The structural and functional characteristics of the sperm plasma membrane were measured by the eosin-test and hypo-osmotic swelling test which were done separately. Sperm cryopreservation was performed on semen samples from two groups of men classified as fertile (n = 20) and subfertile (n = 72), based on their reproductive history and semen analysis according to WHO guidelines. The mean percentage of condensed chromatin, morphologically normal spermatozoa and membrane integrity in all semen samples investigated (n = 92) decreased significantly (p = 0.0001) after freeze-thawing, in comparison to the value observed prior to freezing. By comparing the semen samples between fertile and subfertile patients, significantly (p = 0.0009) greater damage was demonstrated in the subfertile than in the fertile group. Furthermore, no significant difference was observed between the two groups with regard to the morphological alteration and structural as well as functional damage of the sperm membrane. In conclusion, the freeze-thawing procedure significantly affects chromatin structure and sperm morphology, especially in the head and the tail regions, and this may explain the lower fertilization rate and IVF/ICSI outcome when frozen-thawed spermatozoa are used. In addition, this study demonstrates that chromatin condensation is a sensitive parameter for the evaluation of cryodamage of semen samples from fertile and subfertile patients, though subfertile patients with very poor semen characteristics have yet to be studied. It is therefore recommended that chromatin condensation be used as an additional parameter for the assessment of sperm quality after freeze-thawing.

The hypo-osmotic swelling test in recurrent miscarriage

OBJECTIVE

To determine whether there is any association between sperm membrane integrity as determined by the hypo-osmotic swelling test score and unexplained recurrent miscarriage.

DESIGN

Prospective observational study.

SETTING

Tertiary referral center for recurrent miscarriage.

PATIENT(S)

Semen samples from 20 male partners of women who had had three or more first trimester miscarriages of unexplained etiology and semen samples from 20 prospective semen donors of unknown fertility potential.

MAIN OUTCOME MEASURE(S)

Sperm density, sperm motility, sperm morphology, and hypoosmotic swelling test score.

RESULT(S)

There was no difference in the median sperm density, the mean sperm motility, or the mean sperm morphology between the two groups. However, the recurrent miscarriage group had a significantly lower hypo-osmotic swelling test score than the control group.

CONCLUSION(S)

The hypo-osmotic swelling test score is significantly lower in samples from men whose partners have had unexplained recurrent spontaneous abortions. With the exception of cytogenetic abnormalities in peripheral blood karyotype, this is the first study to identify a male factor component in recurrent miscarriage.

Subjecting horse spermatozoa to hypoosmotic incubation: Effects of ouabain

Although hypoosmotic tests are widely used to assess spermatozoal quality in different species, they have not been used extensively in the stallion. Moreover, the role of the Na (+)K (+), ouabain sensitive-ATP-ase in the response of equine sperm to hypoosmotic shock is not well understood. This study tests two hypotheses: 1) that equine spermatozoa will respond to a hypoosmotic medium by swelling of the tail, and 2) that addition of ouabain will increase the percentage of swollen sperm tails. Ejaculates from 3 stallions were collected with an artificial vagina and diluted in Kenney's medium (Time = 0). Aliquots were randomly selected to be incubated in an isoosmotic (297 mOsm) or different hypoosmotic media that were composed of citrate or of citrate wïth fructose. The osmolarity of the hypoosmotic media with citrate ranged from 18 to 96 mOsm, and the medium composed of citrate plus fructose (HOS medium) was of 153 mOsm. Moreover, aliquots of spermatozoa pretreated with ouabain were added to the isoosmotic medium and also to the HOS and the 96 mOsm citrate medium (ORT medium). Incubation of equine sperm in the hypoosmotic media resulted in a time- and osmolarity-dependent swelling of the sperm tail, reaching maximum values after incubation for 20-30 min in both the HOS and ORT media. Ouabain induced a dose-dependent effect on swollen tails and viability in fresh semen and also affected some parameters related to motility. Ouabain also increased the swelling response in a hypoosmotic medium although viability decreased. The percentage of swollen tails after incubation in ORT and HOS media snowed significant correlations to viability, altered acrosomes and total motility, but not to other parameters of horse semen analysis. Our results suggest that hypoosmotic tests could be used to improve standard horse semen analysis. Additionally, Na (+)K (+)-ATP-ase activity could be related to the response against hypoosmotic shock of horse spermatozoa.

Effect of abnormal hypo-osmotic swelling test on fertilization rate and pregnancy outcome in in vitro fertilization cycles

OBJECTIVE

To assess the value of the hypo-osmotic swelling test in predicting fertilization, pregnancy, implantation, miscarriage, and live birth rates in IVF-ET cycles.

DESIGN

Prospective study.

SETTING

Academic tertiary referral center for fertility treatment.

PATIENTS

Three hundred twenty-six couples having IVF-ET for tubal damage or male factor infertility with the female partner < 38 years of age.

INTERVENTIONS

Each male had a hypo-osmotic swelling test performed between 4 and 8 weeks before IVF-ET.

MAIN OUTCOME MEASURES

Fertilization, implantation, miscarriage, and live birth rates.

RESULTS

Eighty of 326 men had abnormal hypo-osmotic swelling tests. An abnormal test was not associated with lower fertilization rates (odds ratio [OR] = 1.14; 95% confidence interval [CI] = 0.97 to 1.14) or pregnancy rate (OR = 0.98; CI = 0.50 to 1.96). However, although couples with a normal test had a miscarriage rate of 26.9% (14/52), in the group with an abnormal test the miscarriage rate was 50.0% (7/14) (OR = 0.37; CI = 0.09 to 1.49). This resulted in a reduction in the live birth rate from 14.1% in the group with a normal test to 11.8% in patients with an abnormal test (OR = 1.23; CI = 0.45 to 3.87).

CONCLUSIONS

The hypo-osmotic swelling test has little value in predicting fertilization in IVF-ET procedures. However, an abnormal test may help predict adverse outcome if pregnancy is achieved.

The spermatozoal volume as indicative of the plasma membrane integrity (modification of the hypoosmotic swelling test). I. Methods

The aim of the present study was to establish a more differentiating indicator of plasma membrane integrity of spermatozoa than the classic version of the hypoosmotic swelling test according to Jeyendraan. Spermatozoa were prepared by density gradient centrifugation (90% Percoll) to select 'fertilization competent' spermatozoa only. After a second washing procedure sufficiently pure sperm cell suspensions were obtained. The volume distributions of these sperm cells were measured with a Coulter Counter at 25 degrees C after adaptation in 300 mosmolar NaCl solution resp. 150 mosmolar NaCl solution for 5 min. These volume distributions showed significantly different patterns for the isotonic and hypotonic stress situation in the simple salt solution. Moreover, the comparison of the response to hypoosmotic stress showed more than four reproducible characteristic patterns, promising well differentiated results for different sperm populations. The new method for the detection of hypoosmotic swelling effect might be a real and valuable functional parameter.

The spermatozoal volume as indicative of the plasma membrane integrity (modification of the hypoosmotic swelling test). II. Diagnostic approach

If using a method of statistical sifting based on the Kolmogoroff-Smirnov test for differentiation of volume distribution curves of a modified HOS-test, different curve types are obtained under isotonic as well as under hypotonic conditions. Arrangement of spermatological parameters of the relevant ejaculates according to the individual curve types reveals significant differences for motility. No correlation can be seen with the results of the microscopic HOS-test. Consequences for the use of the modified HOS-test in medical practice are discussed.

Effects of hypoosmotic incubation on acrosome and tail structure on canine spermatozoa

Hypoosmotic tests are widely used as valuable tests for determining sperm quality in species as varied as the human and the porcine. However, there is little information about the use of these tests in canine spermatozoa. This work evaluates the response of canine spermatozoa in hypoosmotic media in order to introduce the use of the hypoosmotic tests in the canine standard semen analysis. In this way, the incubation of canine spermatozoa in hypoosmotic media containing citrate (ORT medium, osmotic pressure = 100 mOsm) or citrate plus fructose (HOS medium, osmotic pressure = 150 mOsm) resulted in the swelling of the sperm tail. These reactions were time-dependent, reaching maximum percentages after 45 to 60 min. Optimal percentage of tail swelling with minimal effect on the viability of spermatozoa was observed at 100 to 150 mOsm. Response on sperm viability, tail swelling and acrosome detachment to hypoosmotic tests of both undiluted fresh, and 24 h-stored samples were similar. The percentage of swollen tails after both tests showed a good correlation to viability and to gross and progressive motility but not to concentration. However, acrosome detachment after both hypoosmotic tests did not correlate to any of the studied parameters. Our results indicate that the swelling observed after hypoosmotic shock could be used as a useful test in improving the standard semen analysis in the dog.

Methods to evaluate reproductive health of the human male

The proportion of men suffering from subfertility has increased and sperm quality of the general population has decreased rather dramatically during the last decades. Conventional methods to measure sperm concentration, motility, and morphology give a rough estimate of the fertilizing capacity of semen. Objective assessment of motility characteristics and morphometric image analysis may give more precise information, but technology still needs to be refined. Some aspects of the functional capacity of spermatozoa may be impaired before measurable changes occur in their number or morphology. A battery of tests is described to evaluate sperm migration and capacitation, acrosome reaction and acrosin activity, zona adhesion and binding, sperm oolemma fusion, sperm head decondensation, and chromatin make-up. Also methods are described to localize the possible site of impairment of the genital tract. Implementation of these methods may enhance our capability to detect minor effects of environmental hazards on male reproductive health.