Novel parameters of human sperm hypoosmotic swelling test and their correlation to standard spermatogram, total motile sperm fraction, and sperm penetration assay

Codeine-induced sperm DNA damage is mediated predominantly by oxidative stress rather than apoptosis

ABSTRACTBackground: Opioids have been implicated to induce infertility. Although codeine remains the most used opioid for recreational purpose, no study has documented its effect on sperm quality. Elucidating the effect of codeine on sperm cells and the associated mechanisms may provide an insight into preventing drug-induced sperm damage. Twenty-one New Zealand white rabbits were randomized into three groups; control and codeine-treated. The codeine-treated groups received either 4 or 10mg/kg b.w of codeine for six weeks.Results: Codeine treatment led to significant decrease in sperm count, motility, viability, normal morphology, and sperm membrane integrity. This was associated with significant rise in sperm DNA fragmentation, oxidative damage, and caspase 3 activity. The percentage of sperm DNA fragmentation correlates positively with 8-hydroxy-2'-deoxyguanosine, a biomarker of oxidative DNA damage, and caspase 3 activity, a biomarker of apoptosis. The observed correlation was stronger between sperm DNA fragmentation and oxidative DNA damage than sperm DNA fragmentation and caspase 3 activity.Conclusion: This study revealed that chronic codeine exposure causes sperm DNA fragmentation and poor sperm quality primarily via oxidative stress rather than activation of caspase 3-dependent apoptosis. Findings of the present study may explain drug-induced male factor infertility, particularly, those associated with opioid use.

Na,K-ATPase Atp1a4 isoform is important for maintaining sperm flagellar shape

PURPOSE

The aim of this study is to investigate the mechanisms by which the testis specific Na,K-ATPase ion transport system (Atp1a4) controls sperm morphology and shape.

METHODS

Sperm from wild-type (WT) and Atp1a4 knockout (Atp1a4 KO) mice were analyzed morphologically, using light, transmission, and scanning electron microscopy; and functionally, applying sperm osmotic challenge and viability tests. In addition, a sperm proteomic study was performed.

RESULTS

Light microscopy confirmed that sperm lacking Atp1a4 present a bend at the junction of the mid- and principal piece of the flagellum. This bend had different degrees of angulation, reaching occasionally a complete flagellar retroflexion. The defect appeared in sperm collected from the cauda epididymis, but not the epididymal caput or the testis. Transmission and scanning electron microscopy revealed a dilation of the cytoplasm at the site of the bend, with fusion of the plasma membrane in overlapping segments of the flagellum. This was accompanied by defects in the axoneme and peri-axonemal structures. Sperm from Atp1a4 KO mice showed an abnormal response to hypoosmotic challenge with decreased viability, suggesting reduced capacity for volume regulation. Exposure to Triton X-100 only partially recovered the flagellar bend of Atp1a4 KO sperm, showing that factors other than osmotic regulation contribute to the flagellar defect. Interestingly, several key sperm structural proteins were expressed in lower amounts in Atp1a4 KO sperm, with no changes in their localization.

CONCLUSIONS

Altogether, our results show that Atp1a4 plays an important role in maintaining the proper shape of the sperm flagellum through both osmotic control and structurally related mechanisms.

Evaluation of subgroups of the human sperm hypoosmotic swelling test in normozoospermic male cases with recurrent fertilization failure: a prospective case-controlled study

PURPOSE

To compare subgroups of the human sperm hypoosmotic swelling test subgroups in both recurrent fertilization negative infertile cases with normal semen analysis and fertilization positive controls.

METHODS

This was a prospective case-controlled study performed with normospermic 33 previously fertile male (secondary infertility) and 41 infertile men who had undergone two or three unsuccessful in vitro fertilization attempts. HOS test was investigated in 4 subgroups including HOS 1, HOS 2, HOS 3, and HOS 4 according to the degree of sperm tail swelling and compared between the two groups.

RESULTS

Four subgroups were compared and statistical significance was demonstrated in HOS 1, HOS 3 and HOS 4 tests (p < 0.001) in fertile and infertile men. Highest HOS 1 and lowest HOS 4 grades were determined in Group A. However, no statistical significance was determined between two groups in HOS 2 test which was minimal swelling in sperm tails.

CONCLUSIONS

HOS 1, HOS 3 and HOS 4 subgroups of HOS test are reliable and useful methods providing important information regarding the sperm function. A high HOS test 1 grade plus a low HOS test 4 grade should suggest a fertility problem, despite a normal semen analysis. HOS test subgroups provide additional information in normospermic cases with unexplained infertility.

Development of a rapid, sensitive, and reproducible laboratory test kit for the assessment of plasma membrane integrity of human sperm

OBJECTIVE

To develop a rapid, sensitive, and reproducible hypoosmotic swelling test kit for the assessment of plasma membrane integrity of human sperm in vitro.

DESIGN

Prospective comparison of results with the World Health Organization (WHO) method, performed simultaneously.

SETTING

Infertility center in a major city in India.

PATIENT(S)

Couples who presented for infertility evaluation.

INTERVENTION(S)

The sperm tail-coiling pattern representing sperm plasma membrane integrity was analyzed by using different concentrations of NaCl and also with plain double distilled water (ddH(2)O). Hypoosmotic swelling solution with 2% NaCl in ddH(2)O equivalent to 68 Osm/L was selected for further analysis because it provided the highest and the qualitatively best type (g) of tail coiling among the various other options tried in comparison.

MAIN OUTCOME MEASURE(S)

A rapid laboratory test kit for the assessment of plasma membrane integrity of sperm was developed that is equally sensitive and reproducible as that described in the WHO protocol. The test was validated by using different normal and subnormal semen samples and in comparison with the standard WHO protocol.

RESULT(S)

After the screening with different hypoosmotic solutions by using semen samples from fertile volunteers, NaCl (2%) provided the highest and the best types of typical tail coiling, characteristic of sperm with good plasma membrane integrity. The study was then extended to 60 normozoospermic semen samples, which demonstrated a hypoosmotic swelling response of 69.5% +/- 5.23% and 71.5% +/- 4.89%, as per WHO or the present modified method, respectively (coefficient of correlation, r = 0.741). In 13 oligospermic and 18 teratozoospermic subjects, the hypoosmotic swelling response of sperm as per the new method were 36.4% +/- 5.75% and 34.2% +/- 7.78%, respectively, which were comparable to those obtained through the WHO method. There was a 15% drop in viability of sperm after the hypoosmotic challenge (5 min), irrespective of the hypoosmotic solution used. No other morphological alterations in sperm were observed after the hypoosmotic challenge.

CONCLUSION(S)

The new test kit can be used routinely in laboratories for assessment of plasma membrane integrity of sperm in vitro.

Bull semen in vitro fertility after cryopreservation using egg yolk LDL: a comparison with Optidyl®, a commercial egg yolk extender

Low-density lipoproteins (LDL) have been previously isolated and identified as the cryoprotective fraction of yolk. The effect of LDL on sperm motility after freezing-thawing has been reported, but no study has been made to assess the effect of LDL on bull semen fertility. The aim of this study was to evaluate the fertility of bull semen cryopreserved in the presence of LDL. Motility of semen cryopreserved in LDL was analyzed and compared to semen cryopreserved with Optidyl, a commercial extender containing egg yolk. To evaluate the fertilizing ability of semen, we used in vitro fertilization test, whereas acrosome and plasma membrane integrity were also evaluated. The percentage of motile spermatozoa was two fold higher after freezing in LDL than in Optidyl 54.4% versus 30.2% (P < 0.05). The cleavage rate was significantly higher after fertilization with semen frozen in LDL than with Optidyl 63.0% versus 54.8% (P < 0.05). No significant difference was observed on the blastocyst rate after in vitro culture. Integrity of the acrosome and the plasma membrane were maintained in both extenders. In conclusion, LDL preserve bull semen quality and fertilizing ability, allowing also better semen motility, after the freeze-thaw process.

Plasma membrane and acrosomal integrity in bovine spermatozoa with the knobbed acrosome defect

Previous studies have shown that bovine spermatozoa with the knobbed acrosome defect have a reduced ability to bind to and penetrate the bovine zona pellucida. Cryopreserved spermatozoa from a normal control bull (N) and two bulls with the knobbed acrosome defect (K1 and K2) were subjected to a hypoosmotic swelling test (HOST) to evaluate the functional integrity of the plasma membrane. A capacitation assay and a calcium ionophore challenge test was used to determine the ability of spermatozoa to undergo capacitation and acrosome reaction (AR), respectively. The mean percentage of spermatozoa responding to the HOST was significantly higher for Bull N (68.8 +/- 2.4) than for Bulls K1 (36.1 +/- 4.6) and K2 (40.2 +/- 4.7). The mean percentage of capacitated spermatozoa (54.0 +/- 1.8) was significantly higher for the treatment group (incubation in capacitating medium) for Bull N than that of the negative control group (29.5 +/- 1.8). However, there was no difference between the treatment and the negative control groups of the bulls with the knobbed spermatozoa (36.5 +/- 1.4 and 27.1 +/- 3.0 for Bull K1 and 47.5 +/- 3.8 and 35.2 +/- 6.6 for Bull K2, respectively). Although the mean percentage of acrosome-reacted spermatozoa (60.7 +/- 1.3) was higher for the treatment group (receiving calcium ionophore) for Bull N than that of the negative control (29.5 +/- 1.3), there was no difference between the treatment and the negative control groups for the bulls with the knobbed spermatozoa (47.8 +/- 3.3 and 49.3 +/- 5.0 for Bull K1 and 58.8 +/- 10 and 59.5 +/- 9.7 for Bull K2, respectively). A positive correlation existed between the proportion of spermatozoa that did not respond to the HOST and that undergoing a spontaneous AR. Results suggest that spermatozoa with the knobbed acrosome defect have impaired plasma membrane function which predisposes them to premature capacitation and spontaneous AR on incubation after thawing.

Differential effect of common laboratory treatments on hypoosmotic swelling responses of human spermatozoa

PURPOSE

The impact of some of the common laboratory interventions on the hypoosmotic swelling (HOS) responses of human-spermatozoa was investigated.

METHODS

The semen samples underwent different laboratory treatments prior to the standard HOS test, which involved incubation of sperm in the hypoosmotic solution. Fresh semen served as a control for all treatment groups and underwent the same HOS procedure. The HOS-reactive spermatozoa and the type of HOS reactions (swelling types) in each group were identified under a phase-contrast microscope for comparison.

RESULTS

All the seven types of HOS responses documented in fresh semen sperm also occurred in the laboratory-processed sperm. The total HOS responses of sperm that underwent cryopreservation, heat shock, and Percoll wash were significantly different from those of the corresponding control. Percoll washing of semen influenced HOS subtypes a and g; cryopreservation affected subtypes a, b, c, and d; and heat shock altered subtypes a, f, and g. In contrast, prolonged postejaculation and cold shock did not affect any of the HOS responses. None of the treatments influenced the d and e responses.

CONCLUSIONS

These results indicate that the total HOS response value and specific response subtypes are significantly affected by some of the laboratory treatments but not others.

Review: in vitro spermicidal tests

This review analyzes in vitro spermicidal tests that have been used to evaluate the spermicidal activity of contraceptive products. Special requirements and processes in numerous technologies were also reviewed. Nonoxynol-9 (N-9) was used as an example of a vaginally delivered spermicidal agent, and its spermicidal potency was compared by various spermicidal tests, such as Sander-Cramer, computer-assisted semen analysis, hypoosmotic swelling test, cervical mucus penetration test, and flow cytometry, and advantages and disadvantages of each test were specified. This provides an insight into the different aspects of sperm functionality on which each spermicidal agent exerts its activity. A rationale of the best combination of in vitro spermicidal tests, with particular emphasis on a simple and efficient strategy that targets the complete fertility control, was explained.