Ofloxacin: the next generation of antibiotic in sperm and embryo cultures for assisted reproductive technologies

OBJECTIVE

To analyze the effect of different concentrations of ofloxacin on sperm kinematic parameters and to determine the embryotoxicity of ofloxacin at physiologic and at 100x concentrations.

DESIGN

Prospective comparative study.

SETTING

Clinical and academic research environment.

PATIENT(S)

Pooled cryopreserved donor sperm (n = 7).

INTERVENTION(S)

Human sperm were processed through two-layer discontinuous Percoll gradients, and the resultant pellet was resuspended in either HEPES-buffered human tubal fluid medium containing different concentrations of ofloxacin or the control medium. After measuring the kinematic parameters, the percentages of apoptosis and viability were obtained. Next, the sperm DNA was extracted and polymerase chain reaction of beta-globin gene was performed followed by denaturing gradient gel electrophoresis. Mouse embryos recovered at the one-cell pronuclear or zygote stages were cultured in the presence or absence of ofloxacin up to the hatched blastocyst stage and differences in development were recorded.

MAIN OUTCOME MEASURE(S)

Sperm kinematic parameters, sperm beta-globin gene, and number of embryos reaching the hatched blastocyst stage.

RESULT(S)

The number of embryos exposed to control and physiologic ofloxacin concentrations showed comparable excellent growth. However, the 100x concentration significantly arrested development. Rates of sperm viability and apoptosis measured 48 hours after exposure to the above concentrations were not different from controls. No differences were noted in the sperm kinematic parameters of sperm exposed to ofloxacin concentrations (1x, 10x, and 100x) or control medium after 0, 4, and 48 hours of incubation. Denaturing gradient gel electrophoresis of beta-globin genes from DNA exposed to varying ofloxacin concentrations failed to show any point mutations.

CONCLUSION(S)

Ofloxacin was embryotoxic at pharmacologic concentrations (100x). At physiologic or higher concentrations, ofloxacin appears to be safe and does not affect sperm kinematic parameters when compared with controls. This may indicate that sperm motility parameters alone cannot be relied on to evaluate the effects of drugs on fertility and that in vitro embryologic studies are essential. Ofloxacin at any concentration did not alter the rates of sperm apoptosis or viability. Ofloxacin does not appear to be mutagenic as evidenced by the beta-globin gene analysis.

Enhanced fertility after heat-induced hyperactivation

OBJECTIVE

To determine sperm hyperactivation, kinematic parameters, and fertilizing capacity after pretreating sperm at 40 degrees C for 4 hours.

DESIGN

Prospective study involving pooled donor sperm that were colloid washed and incubated at either 23 degrees C (control) or 40 degrees C (heat-treated) for 4 hours as pretreatment. After incubation, analyses were performed with a computer-assisted sperm analyzer, whereas separate portions of sperm were evaluated with the sperm penetration assay at 37 degrees C.

SETTING

Clinical and academic research environment.

PATIENT(S)

Cryopreserved-thawed sperm from different donors (n = 5).

MAIN OUTCOME MEASURE(S)

Sperm kinematic and fertilizing parameters.

RESULT(S)

Heat pretreatment of sperm resulted in over 22 times higher hyperactive motility at hour 4 compared with the control. The other kinematic parameters were also different. The heat-pretreated sperm group had a significantly higher percent penetration of zona-free oocytes with more swollen sperm heads per oocyte and enhanced sperm binding.

CONCLUSION(S)

The results showed that hyperactivation was induced by pretreatment of sperm with 40 degrees C heat, suggesting the involvement of heat factors in hyperactivation. The fertilizing capacity of sperm may be improved by the mild heat pretreatment when marked by the presence of heat-induced hyperactivation.

Heat-induced hyperactivation

PURPOSE

The objectives of this study were (1) to determine the sperm hyperactivation and related kinematic parameters at 40 degrees C after using four sperm wash procedures and (2) to correlate the heat-induced hyperactivation data with cases of clinical pregnancies from either artificial insemination or standard in vitro fertilization (IVF).

METHODS

Semen samples (n = 51) were collected by ejaculation, and semen analyses were carried out to determine the pretreatment data. Sperm kinematic measurements were performed using the Hamilton Thorn HTM-C computer-aided sperm analyzer. Hyperactivation was determined using the sort module on the HTM-C. Membrane integrity was assessed using the hypoosmotic sperm swelling procedure. Sperm morphology and acrosomal status were also determined using the Spermac stain. Each semen specimen was divided and processed through either the swim-up wash, the 1-h test-yolk buffer (TYB) wash, the 1 mg/ml pentoxifylline stimulant procedure, or the two-layer 90:47% gradient colloidal solution procedure. The washed sperm were incubated at 25 or at 40 degrees C for 4 hr. After incubation, kinematic parameters were assessed for the posttreatment data. Semen specimens were obtained on different occasions for artificial insemination or standard IVF. Data from intracytoplasmic sperm injection cases were not included to avoid confounding factors. Live births and/or pregnancies with fetal heart-beat examined by ultrasound were considered clinical pregnancies.

RESULTS

Heat-induced hyperactive motility was significantly higher in sperm of the male partner of pregnant (n = 7) patients compared with nonpregnant (n = 44) patients (mean +/- SE, 10.0 +/- 3.3 versus 5.5 +/- 0.8%) after TYB processing followed by 4 hr of incubation at 40 degrees C. This was also observed after colloid (Percoll) processing (11.6 +/- 4.6 versus 5.8 +/- 0.8%). There were no differences in hyperactivation after 4 hr at 23 degrees C between pregnant and nonpregnant cases. Parameters such as count, volume, motility, viability, and acrosomal status were not different for the groups. However, the percentage of sperm with normal morphology (WHO classification) was twice as high in the pregnant group versus the nonpregnant group.

CONCLUSIONS

Heat-induced hyperactivation was associated with fertile sperm and was predictive of pregnancy obtained after artificial insemination or IVF. The association was evident only after TYB or Percoll sperm processing. The study could not confirm the finding of significant decreases in motility after heat treatment of sperm derived from infertile males. The mechanism for heat-induced hyperactivation did not involve membrane integrity or the sperm acrosome, although an involvement of heat shock proteins was postulated. Interestingly, there were no pregnancies when sperm did not exhibit heat-induced hyperactivation.

Silane-coated silica particle colloid processing of human sperm

PURPOSE

The purpose of this study was to determine differences in the quality of human sperm processed through different lots of silane-coated silica particle colloid solutions. The objectives were to compare (a) sperm kinematic parameters, (b) the sperm acrosome status, (c) the membrane integrity of the head and tail regions, (d) the DNA normality, and (e) the heat-inducible hyperactivation motility after processing sperm through either a Silane-coated silica particle colloid solution, a Percoll solution, or a simple centrifuge sperm wash (control).

METHODS

Sperm cells were derived from pooled cryopreserved-thawed specimens of several donors (n = 10). The pooled sperm were divided and processed through either the centrifuge wash, the 90:47% two-layer Percoll, or one of three lots of silane-coated silica particle colloidal solutions from three vendors. Aliquots of sperm cells were analyzed using the Hamilton-Thorn HTM-C motility analyzer for differences in kinematics and hyperactivation. Sperm were also analyzed for membrane integrity at both head and tail regions, normal morphology, acrosome status, and viability. Sperm undergoing apoptosis were determined using the acridine orange stain. Processed sperm were also incubated at 40 degrees C for 4 hr and the quality of the sperm was assessed using the heat-induced hyperactivation and motility parameter.

RESULTS

The data showed that after sperm processing, the number of sperm recovered was higher for the three lots of colloids (silane-coated silica particle colloid solutions) compared with Percoll processing. Total sperm motility was higher in the colloidal washes compared with the control. There were no differences in motility between Percoll- and colloid-processed sperm. In contrast, the percentages of sperm exhibiting progressive motility or hyperactivation varied among the different lots of colloid solutions. The Percoll wash solution yielded the highest percentage of sperm with intact tail membranes, whereas some lots of colloid solutions disrupted sperm head membranes. The percentages of sperm undergoing apoptosis varied for the different lots of colloid solutions. There was a marked increase in hyperactivation associated with one colloid solution after heat induction.

CONCLUSIONS

The results demonstrated variability in the different lots of silane-coated silica particle colloid solutions for processing sperm. Each lot of colloid solution excelled at improving different sperm parameters. The silane-coated silica particle colloid solutions were shown to be effective in recovering motile sperm compared with Percoll but the types of motility and sperm quality varied for the different lots of colloid solutions. Due to the variability in lots of silane-coated silica colloid solutions, reported studies based on only one lot or one source of colloid solution may be difficult to interpret. Furthermore, it may be advantageous to select the best lot of silane-coated silica particle colloid solution to produce the highest number of sperm exhibiting the ideal parameters for use in assisted reproduction technologies.

Antibiotics: effect on cryopreserved-thawed human sperm motility in vitro

OBJECTIVE

To analyze the motility and fertilizing capacity of sperm treated with different antibiotics.

DESIGN

Prospective comparative study.

SETTING

Clinical and academic research environment.

PATIENT(S)

Pooled cryopreserved donor sperm (n = 14).

INTERVENTION(S)

Sperm were washed with Percoll and resuspended in HEPES-buffered human tubal fluid medium containing either amoxicillin, ofloxacin, ciprofloxacin hydrochloride, nitrofurantoin monohydrate, doxycycline hyclate, cefuroxime axetil, or control medium.

MAIN OUTCOME MEASURE(S)

Sperm kinematic and fertilizing parameters.

RESULT(S)

Sperm hyperactivation was decreased in physiologic concentrations of ciprofloxacin hydrochloride and doxycycline hyclate over the course of 48 hours. At pharmacologic concentrations, ciprofloxacin hydrochloride, cefuroxime axetil, and nitrofurantoin monohydrate adversely affected motility with decreased rapid progression. Cessation of motility occurred in cefuroxime axetil and nitrofurantoin monohydrate. Sperm hyperactivation was also absent. Cefuroxime axetil decreased the percentage of intact acrosomes. In contrast, physiologic doses of ciprofloxacin hydrochloride or ofloxacin enhanced sperm fertilizing capacity.

CONCLUSION(S)

Ciprofloxacin affected hyperactivation by altering membrane properties, whereas doxycycline inhibited the capacitation process. Cessation of motility in cefuroxime axetil was linked to disrupted sperm head membranes. Sperm motility and fertilizing capacity were decreased in nitrofurantoin because of decreased metabolism. The positive effect of ofloxacin on fertilizing capacity did not involve changes in acrosome.

Transfection of the inner cell mass and lack of a unique DNA sequence affecting the uptake of exogenous DNA by sperm as shown by dideoxy sequencing analogues

PURPOSE

The purpose of this study was to determine whether exogenous DNA internalized into blastocysts after transference from DNA-carrier sperm are localized at the inner cell mass or trophoblast cells and to identify differences in uptake of exogenous DNA fragments by sperm due to unique DNA sequences.

METHODS

Mouse blastocysts at the hatching stage were exposed to migrating human sperm cells carrying exogenous DNA fragments synthesized from the E6-E7 conserved gene regions of human papillomavirus (HPV) types 16 and 18. After an interaction period of 2 hr, the transfected blastocysts were washed several times to remove extraneous sperm and the blastocysts were dissected into groups of cells derived from the inner cell mass and trophoblasts. The cells were analyzed by polymerase chain reaction (PCR) for the presence of HPV DNA fragments. In the second part of the experiment, thawed donor (N = 10) sperm cells were pooled, washed, and divided into two fractions. The first (control) fraction was added with formalin and further divided and added with a 35S-radiolabeled G, A, T, or C sequencing mixture. The second fraction was similarly treated but the formalin step was omitted from the treatment. After an hour of incubation at 37 degrees C, the sperm specimens were washed several times by centrifugation and DNA extracted by the GeneReleaser method. The extracted DNA were processed on sequence gels, and the autoradiographs analyzed.

RESULTS

Mouse blastocysts transfected by carrier sperm with DNA from HPV types 16 and 18 showed localization of the HPV DNA to both the inner cell mass and trophoblast cells. Negative controls consisting of untreated human sperm and untreated mouse blastocysts did not reveal any evidence of HPV DNA. The positive sperm control generated expected DNA fragments from HPV types 16 and 18. In the second experiment, the intensities of the DNA fragments in the G, A, T, and C columns from low to high molecular weights were not different from the positive control bands. Band intensities of the four sequencing columns were similar. Formalin pretreatment of the sperm inhibited uptake of the DNA fragments from the smallest to the largest DNA molecules.

CONCLUSIONS

Exogenous DNA taken into blastocysts are localized to both the inner cell mass and trophoblast cells. Only live sperm exhibited the capacity to carry various sizes of exogenous DNA, suggesting the involvement of active cell membrane mechanism in the transference process. The results showed that DNA fragments terminating in any of the four nucleotides were equally taken up by the sperm cell. Fragments of DNA produced by the sequencing reaction failed to identify a unique DNA sequence that would facilitate or inhibit the sperm from taking up exogenous DNA.

Prevalence of mycoplasma conserved DNA in malignant ovarian cancer detected using sensitive PCR-ELISA

Mycoplasmas are tiny polymorphic prokaryotic organisms (0.2-0.3 microm) that lack a cell wall and reside ubiquitously at the cell membrane or internalized into the cell. The organisms have been implicated in many diseases including functioning as cofactors catalyzing the HIV disease state. The oncogenic potential of mycoplasmas was only recently realized when they were shown to cause chromosomal changes and in vitro cell transformations through gradual progressive chromosomal loss and translocations. While a recent study linked mycoplasmas with gastric cancer, the association between mycoplasmas and ovarian cancer has not been established. Recently, a commercial assay which combined polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA) methods was developed for the detection of mycoplasmas. The present objective was to determine the prevalence of mycoplasmas in archived paraffin-embedded malignant ovarian cancer tissue. The combined PCR-ELISA procedure was used with consensus primers targeting for 15 species of mycoplasmas and acholeplasmas. Archived human malignant ovarian cancer tissues (N = 27 cases) embedded in paraffin blocks were processed, and DNA was extracted and the presence of DNA verified. The extracted DNA specimens were randomly divided into three groups for analyses. PCR-ELISA assays were performed on extracted DNA together with appropriate negative and positive controls. The results showed mycoplasmas were present in 59.3% of the malignant ovarian cancer specimens. PCR-ELISA analysis of Neisseria gonorrhea and Chlamydia trachomatis controls did not produce cross-reacting false-positive results. The results suggest an association between mycoplasmas and malignant ovarian cancer. A 59.3% prevalence rate was demonstrated for mycoplasmas in paraffin-embedded ovarian cancer tissues. The mechanism involved in oncogenesis by mycoplasmas remains to be elucidated.

Polymerase chain reaction enzyme-linked immunosorbent assay detection of mycoplasma consensus gene in sperm with low oocyte penetration capacity

OBJECTIVE

To determine the prevalence of mycoplasmas in washed sperm and to compare the penetration of zona-free hamster oocytes by sperm with and without mycoplasmas.

DESIGN

Prospective comparative study.

SETTING

Clinical and academic research environment.

PATIENT(S)

Semen from 34 male patients.

INTERVENTION(S)

Specimens were divided, Percoll washed, and scanned for differences in kinematic parameters. Sperm DNA was extracted and assayed for mycoplasma DNA using the polymerase chain reaction-ELISA method targeting the consensus gene of 15 mycoplasma species. Remaining sperm were processed by centrifuge, Percoll, or TEST (TES and Tris) Yolk Buffer (TYB) and assessed for penetration capacity.

MAIN OUTCOME MEASURE(S)

Detection of mycoplasma DNA.

RESULT(S)

Mycoplasma DNA was detected in 29.4% of the Percoll-washed sperm. The penetration of oocytes by mycoplasma-positive sperm (59.5% +/- 17.3%; mean +/- SEM) was less than mycoplasma-negative sperm (86.8% +/- 5.4%) in the TYB-processed group.

CONCLUSION(S)

Mycoplasma DNA is demonstrated in almost a third of the Percoll-washed sperm. Because there were no other cell types except sperm, the results suggest that the mycoplasmas were either internalized or attached to the membranes. The reduced penetration by mycoplasma-positive sperm after 48-hour TYB suggest mycoplasmas required time to affect sperm function. Similarities between hypo-osmotic swelling and between kinematic parameters suggest that the mechanism does not involve differences in membrane integrity and in motility patterns.

Analysis of the flow cytometer stain Hoechst 33342 on human spermatozoa

Several procedures exist for processing sperm cells for sex preselection. Flow cytometric separation using the fluorochrome stain Hoechst 33342, chemically known as bisbenzimide, is the most promising. The objective of this study was to determine the effect of bisbenzimide on spermatozoa assessed by means of the sperm survival test and to analyse the beta-globin gene in sperm DNA after exposure to increasing concentrations of bisbenzimide. Donor (n = 16) sperm specimens were pooled and washed in a discontinuous Percoll gradient 95:47%, divided and incubated in tubes containing bisbenzimide at concentrations 0 (control), 0.9, 9, 90, 900 and 9000 microM at 25 degrees C and scanned on a computer-aided sperm motility analyser at 0, 1, 4 and 24 h. Spermatozoa were also incubated in a known mutagen, ethidium bromide, as positive control. After 24 h of incubation, the treated sperm cells were processed through DNA extraction and polymerase chain reaction (PCR) performed with primers targeting the beta-globin gene. The amplified DNA products were analysed for evidence of mutation in 5% polyacrylamide gel electrophoresis and 20:80 denaturing gradient gel electrophoresis (DGGE) and further confirmed in 30:40 DGGE. The results showed complete cessation of motility in sperm incubated in the presence of 900 microM or higher concentrations of bisbenzimide. The beat cross frequency sperm parameter was significantly different at the 90 microM or higher concentration of bisbenzimide compared with the control. At concentrations < 900 microM bisbenzimide, there were no differences in the remaining sperm kinematic parameters (percentage rapid progressive, percentage total progressive, sperm velocities, linearity, straightness, amplitude of lateral head displacement and percentage hyperactive motility). PCR and DGGE analyses of spermatozoa treated with bisbenzimide showed no evidence of mutation in the representative region of the beta-globin gene at concentrations < 900 microM. The data suggest an inhibitory effect of bisbenzimide on human sperm motility at 900 microM or higher concentrations of bisbenzimide. The decrease in sperm motility and rapid progression were not due to changes in pH. Point mutation in the representative region of the beta-globin gene in human spermatozoa was detected only at high concentrations (> or = 900 microM) of bisbenzimide. The data suggest that incubating sperm in low concentrations of bisbenzimide (< 90 microM) for up to 24 h does not significantly affect all the sperm kinematic parameters including the beat cross frequency parameter when compared with the control.

The effects of Vero cell co-culture on human zygotes resulting from in vitro fertilization and oocytes following subzonal insemination

A variety of co-culture systems have been devised to enhance the human embryo development in vitro. Vero cells were selected because they can be highly controlled and are easy to handle. To evaluate the embryotrophic effects of Vero cell monolayers, when they were co-cultured with human in vitro fertilized zygotes or subzonal inseminated oocytes. Total 1695 two-pronuclear embryos resulting from in vitro fertilization were cultured with Vero cells or medium alone for 24 hours. Similarly, sixty-six two-pronuclear embryos resulted from subzonal insertion of sperm (SUZI) with co-culture starting immediately following SUZI were compared with fifty-two two-pronuclear embryos resulted from SUZI, without co-culture. The numbers of blastomere and morphology of embryos were compared between the co-culture group and control group using student's t-test. Cell numbers in each embryo were greater in the IVF/co-culture group than in the control group (4.01 +/- 1.32 vs. 3.86 +/- 1.45, p < 0.05). The rates of poor quality embryo with major fragmentation were lower in the co-culture group than in the control group(11.5% vs. 19.9%, p < 0.001, for IVF embryos; 9% vs. 27%, p < 0.005, for SUZI oocytes). Co-culture SUZI oocytes on Vero cells prior to fertilization did not positively influence embryo cleavage, but improved embryo quality. We conclude that Vero cells can enhance human embryo development; however, the period for one-day or two-day co-culture is too short to provide a maximal support. Short term co-culture did not increase implantation rates. Immediate co-culture following SUZI might somewhat rescue the microinseminated oocytes. However, a longer duration of co-culture is necessary to exert the maximal effects on embryo development and implantation.

Sperm kinetics and morphology before and after fractionation on discontinuous Percoll gradient for sex preselection: computerized analyses

The multiple-layer discontinuous Percoll density gradient centrifugation procedure is being used for gender selection and several reports suggested separation efficiencies of over 77%. The mechanism involved in the separation of X- and Y-bearing sperm using this method seems to be the difference in sperm head dimensions or motility but supporting data are inconsistent. The specific aims of the study were to evaluate the head dimensions of sperm at the upper and lower fractions after the 8-layer Percoll gradient procedure for sex preselection and to ascertain the kinematic parameters and tail lengths of sperm derived from the 2 separate Percoll fractions. Sperm cells were obtained from thawed donor specimens (N = 20) and were layered on top of the 8-layer discontinuous Percoll gradient, which ranged from 34 to 85% in increments of 7%. After centrifugation, the resuspended sperm cells derived from the upper and lower fractions of the Percoll gradient were analyzed on the Hamilton Thorn HTM-C analyzer for differences in sperm motility patterns and sperm head dimensions. Aliquots of sperm from the 2 fractions were fixed and stained using the Spermac stain, and the lengths of each sperm tail (N = 600) were measured on the HTM-C analyzer. Sperm derived from the bottom Percoll (X) fraction had a threefold higher (p < .05) percent motility when compared with sperm from the top (Y) fraction. Sperm derived from the bottom (X) fraction maintained the higher percentage motility after 24 h of incubation. The percent total progression, rapid progression, and hyperactivation were also significantly higher (p < .05) in sperm from the bottom (X) fraction. Similarly, the curvilinear (Vcl), average path (Vap) and straight line (Vsl) velocities were significantly faster in sperm (p < .05) from the bottom (X) fraction. In contrast, the percent linearity and straightness were significantly (p < .05) higher for the top (Y) fraction. Sperm from the bottom (X) fraction have shorter (p < .07) tail length (1.6% difference) when compared with sperm from the top (Y) fraction. Although the dimensions of the sperm head from the bottom (X) fraction were numerically greater than top fraction sperm, they were not significant (p > .05). The results suggest that bottom (X) fraction sperm derived from the 8-layer discontinuous Percoll gradient for sex preselection have higher motility, progression, and hyperactivation when compared with top (Y) fraction sperm. The bottom (X) fraction sperm have greater longevity in motility and have shorter tails, supporting earlier hypotheses of sex differences in sperm parameters. However, the present data do not support observations of differences in sperm head dimensions in sperm processed for sex preselection, and an inference of a larger sperm due to more chromosome material originating from the X chromosome cannot be made.

Coculture of human spermatozoa with reproductive tract cell monolayers can enhance sperm functions better than coculture with Vero cell monolayers

PURPOSE

In order to develop a better system for support of human sperm function in vitro, we conducted studies to evaluate whether reproductive tract cells are better than non-reproductive tract cells as an adjunt in that regard.

METHODS

Human spermatozoa were cocultured with Vero cells, with human oviduct cells and endometrial cells, and without cells (control) for either 1, 4, or 24 hr. Sperm motility was then analyzed with a computer-aided sperm analyzer (CASA-Hamiliton Thron, HTM IVOS Motility Analyzer). Aliquots of spermatozoa incubated for 24 hr were also stained with Hoechst 33258 and FITC-PNA to evaluate the status of acrosome in live cells.

RESULTS

Significant differences (P < 0.05) between the oviduct cell and the control groups after 24 hr were evident in the curvilinear velocity (VCL) (81.4 +/- 13.4 vs 60.0 +/- 14.1 microns/sec) and amplitude of lateral head displacement (ALH) (5.2 +/- 0.6 vs 4.1 +/- 0.5 microns). The incidence of acrosome reaction of live sperm was significantly higher in the endometrial cell group than in the controls (25.4 +/- 9.9 vs 6.6 +/- 2.4%; P < 0.001).

CONCLUSIONS

Coculture with human reproductive tract cells seems to improve some functional parameters of human spermatozoa. Coincubation with such cell lines, especially oviduct cells, might be a feasible approach to optimization of human spermatozoa for assisted fertilization using subfertile or frozen-thawed samples. We think coincubating human spermatozoa with a human reproductive tract cell line, especially oviduct cells, might be a feasible approach in preparing human spermatozoa for assisted fertilizatioin in subfertile and frozen-thawed semen samples.

Correlation between intact sperm acrosome assessed using the Spermac stain and sperm fertilizing capacity

Accurate determination of sperm acrosomal status is important in fertility studies. The objective was to correlate the percentage of intact acrosome assessed using the new Spermac stain with the capacity of sperm to fertilize oocytes. Sperm specimens were processed either by centrifuge wash, 48:95 Percoll gradient or test yolk buffer (TYB) wash, and tested using the zona-free hamster oocyte assay. The results indicated a correlation between the percentage of sperm with intact acrosome reaction and the percentage of sperm penetrating the oocytes in the TYB-washed group. The data suggest the usefulness of the Spermac stain for assessing the acrosomal status and in predicting the fertilizing capacity of the sperm.

The follicle-stimulating hormone receptor gene is polymorphic in premature ovarian failure and normal controls

OBJECTIVE

To examine the FSH receptor gene for detectable abnormalities in women with premature ovarian failure.

DESIGN

Study of genomic DNA from controls and from patients with 46,XX premature ovarian failure (POF).

SETTING

Clinics and laboratories of university gynecology and obstetrics departments.

PATIENTS

Twenty-one women with 46,XX POF and 40 normal fertile controls.

INTERVENTIONS

Deoxyribonucleic acid was analyzed in patients and controls by Southern blot analysis, polymerase chain reaction (PCR), and denaturing gradient gel electrophoresis. Southern blots were hybridized with the FSH receptor complementary DNA and other smaller DNA probes. Exons 1, 5 to 6, and 10 were amplified by PCR and electrophoresed on agarose gels. Polymerase chain reaction products from exons 1 and 10 were electrophoresed on denaturing gradient gels.

MAIN OUTCOME MEASURES

Fragments obtained by Southern blot analysis and PCR were compared in patients and controls. Polymerase chain reaction fragments electrophoresed on denaturing gels also were compared in patients and controls.

CONCLUSIONS

No FSH receptor gene deletions or other mutations were identified in women with POF. Southern blots containing PstI- and HindIII-digested DNA revealed restriction fragment length polymorphisms in both patients and controls. Denaturing gradient gel electrophoresis analysis of PCR fragments of exon 10 also demonstrated DNA sequence polymorphisms in both patients and controls. Follicle-stimulating hormone receptor gene deletions are not common in women with POF, although the gene is polymorphic. We cannot exclude point mutations in other regions of the FSH receptor gene in some patients with POF.

Blastocysts exhibit preferential uptake of DNA fragments from the E6-E7 conserved region of the human papillomavirus

The objective of the study was to determine if embryos at the blastocyst stage differentially took up exogenous human papillomavirus (HPV) DNA derived from the different HPV types and to determine whether the capture process was active or passive. In vivo fertilized mouse embryos were cultured to the blastocyst stage in vitro. The mouse blastocysts were incubated for 2 hr in the presence of a mixture of exogenous DNA fragments derived from HPV types 6b, 11, 16, and 18. The blastocysts were rigorously washed and analyzed for differential uptake of HPV gene sequences using the polymerase chain reaction (PCR) and polyacrylamide gel electrophoresis. PCR analysis detected HPV type 18 in only 40% of the blastocyst groups while detecting the other HPV types in 100% of the blastocysts. The negative control group did not show HPV DNA after PCR ruling out possible PCR artifacts. Formalin-fixed blastocysts also showed uptake of HPV DNA. In conclusion, the data suggest a role for embryos as passive vectors for foreign DNA and that the degree of DNA uptake varies with different types of HPV DNA.

Sperm as a noninvasive gene delivery system for preimplantation embryos

OBJECTIVE

To determine if sperm could be manipulated to be a noninvasive transport carrier for the delivery of gene fragments to the blastocyst.

DESIGN

Sperm cells carrying foreign DNA fragments from human papillomavirus (HPV) types 16, 18, 31, and 33 were allowed to migrate from one end of an artificial reproductive tube and to come in contact with hatching mouse blastocysts at the other end of the tube. The blastocysts were then washed and analyzed for the presence of the foreign DNA fragments.

SETTING

Clinical and academic research environment.

MAIN OUTCOME MEASURE

Detection of amplified products from transferred foreign DNA using the polymerase chain reaction and primers targeted at the E6-E7 region for different HPV types.

RESULTS

Polymerase chain reaction analyses showed transference of DNA HPV type 18 to the blastocysts. Not all types of DNA fragments were transferred equally.

CONCLUSION

The results suggested the possibility of using sperm as a noninvasive gene delivery system for passing on gene fragments to preimplantation embryos. It was demonstrated that certain DNA fragments were easier to deliver than others, indicating the necessity for exploring all the factors involved in the mechanism of the transference process. The study also serves to highlight the possibility of unintentional transmission of viral or bacterial DNA to the developing embryo via the sperm.

Human papillomavirus gene sequences in washed human sperm deoxyribonucleic acid

The present study demonstrated the presence of HPV gene sequences in Percoll-washed sperm cells using polymerase chain reaction primers targeting smaller gene regions. Up to 64% of the sperm specimens were shown to contain gene sequences indicative of the presence of HPV. Human papillomavirus type 16 was detected about twice as often as HPV type 18. The results suggest the possible role of sperm as a vector for HPV.

White blood cells in semen affect hyperactivation but not sperm membrane integrity in the head and tail regions

The presence of high numbers of peroxidase-positive PML in ejaculated semen significantly reduced sperm HA, an important step leading to sperm capacitation. Sperm membranes at both the head and tail regions, as assessed by the hypo-osmotic viability parameter and the hypo-osmotic sperm swelling test, respectively, were not affected by peroxidase-containing leukocytes. Sperm motility was not affected, but sperm curvilinear and straight line velocity parameters were reduced in the presence of high concentrations of leukocytes in the ejaculate. The results suggested that the effect of leukocytes on sperm was through a reduction in sperm hyperactive motility but not through alterations in the sperm head and tail membranes.

The relationship between human sperm fertilizing capacity and histocompatibility linked antigen (HLA) alleles gene sequences

Heterodimer membrane glycoproteins expressed from hypervariable genes located in the histocompatibility linked antigen (HLA) class II genes on chromosome 6 have been shown to induce activation of lymphocytes and are involved in human sperm binding processes. The objective was to identify an association between HLA-DQA1, -DRB1 or -DPB1 genes and sperm kinematic parameters and sperm penetration of oocytes. The results showed reduced sperm hyperactivation and decreased sperm penetration of zona-free oocytes when the HLA-DRB1 allele was present. The reduced hyperactive motility was not attributed to alterations in sperm kinematic parameters. In contrast, the HLA-DPB1 gene only affected sperm count, linearity of movement and sperm head dimensions. HLA-DQA1 had no effect on the sperm parameters. The data suggest a link between HLA-DRB1 and HLA-DPB1 genes and sperm concentration, sperm movement characteristics and fertilizing capacity.

Effects of pentoxifylline on sperm motility and hyperactivation in normozoospermic and normokinetic semen

OBJECTIVE

To determine the effects of in vitro incubation with pentoxifylline on sperm motion characteristics of spermatozoa from normozoospermic, normokinetic specimens.

DESIGN

Prospective, controlled experiment.

SETTING

Andrology laboratory, university-based fertility center.

PARTICIPANTS

Healthy, untreated male partners of couples attending the fertility center.

INTERVENTION

Each specimen was washed, pelleted by centrifugation, then resuspended in human tubal fluid medium (HTF). Two portions were incubated at 37 degrees C, one with pentoxifylline (final concentration = 1 mg/mL = 3.6 mM) and the other without pentoxifylline (control). After 1 hour, the pentoxifylline-treated portion was divided: one half was washed to remove pentoxifylline, then further incubated in HTF; the other half remained incubated in HTF with pentoxifylline.

MAIN OUTCOME MEASURES

Motility, hyperactivation, amplitude of lateral head displacement (ALH), curvilinear velocity (VCL), straight line velocity (VSL), linearity (LIN), beat-cross frequency.

RESULTS

Incubation with pentoxifylline did not increase motility, VSL, LIN, or beat-cross frequency but did significantly increase HA, VCL, and ALH at 1, 2, and 4 hours, compared with control. Incubation in control medium without pentoxifylline did not significantly increase any of the parameters measured. After 24 hours of incubation with or without pentoxifylline, all parameters measured were significantly decreased, with the exception of LIN.

CONCLUSIONS

Pentoxifylline does not increase percentage motility of washed spermatozoa in capacitation medium. Enhancement of sperm HA by pentoxifylline in capacitation medium occurs with normozoospermic, normokinetic semen specimens. This effect persists for up to 4 hours when pentoxifylline is removed from the medium after 1 hour of incubation.

Clinical pregnancy rate after the double method wash and intrauterine insemination

The protocol for intrauterine insemination (IUI) involves sperm processing using different methods that have produced varying results. These sperm wash methods do not take into consideration the problems of the exact timing of ovulation and the requirements of sperm cells at different stages of capacitation. The objectives of this study were 1) to use the double method wash previously reported to produce a mixture of different populations of sperm cells and determine the pregnancy outcome after IUI and 2) to compare the sperm kinematic parameters after the double method wash with those after the centrifuge (or whole-population) wash method. Patients were divided into either the double method group (n = 119) or the centrifuge method group (n = 76). The Hamilton-Thorn HTM-C automated sperm motility analyzer (Hamilton-Thorn Research, Danvers, MA) was used to analyze sperm motility parameters. Pregnancy outcomes were evaluated after controlled ovarian stimulation and IUI. An almost 2-fold increase was seen in the pregnancy rate with the double method wash compared with the centrifuge method wash. Sperm motility and velocity were also enhanced in the double method wash groups. The results support the usefulness of the double method wash for the preparation of sperm for IUI.

Uptake of exogenous human papilloma virus L1 DNA by oocytes and detection by the polymerase chain reaction

OBJECTIVE

The purpose of this study was to determine if oocytes were capable of taking up exogenous DNA such as human papillomaviral (HPV) DNA and evaluate the zona pellucida as a barrier to the entry of foreign DNA into the oocyte.

METHODS

The experiment consisted of four groups of hamster oocytes exposed to HPV DNA fragments: Group A, zona-free oocytes (n = 5); Group B, oocytes with an intact zona pellucida (n = 5); Group C, oocytes fixed in 4% buffered formalin solution for 20 min (n = 5); and Group D, zona-free oocytes (n = 4). Group C oocytes served as an internal control to ensure adequate washing of the oocytes after incubation.

RESULTS

The zona pellucida was not a barrier to foreign DNA molecules. The PCR did not detect L1-HPV and beta-globin gene sequences in the untreated hamster oocyte. Uptake of the smaller DNA fragments such as that amplified from the beta-globin region was independent of active oocyte cell processes.

CONCLUSION

Oocytes cultured in vitro can passively take up exogenous DNA fragments. The results suggest a possible role of oocytes as vectors for foreign DNA.

Assessment of sperm for cryopreservation using the hypoosmotic viability test

In summary, the hypoosmotic viability parameter was significantly correlated with the outcome of the thawed sperm motility. The prefreeze supravital staining for sperm viability and the hypoosmotic sperm swelling test were not predictive of the thawed sperm total motility. The hypoosmotic viability parameter was not correlated to the postwarmed sperm motility after refrigeration. The results indicated that the integrity of the sperm membranes at the head were more important than the tail membrane.