Microdrop-vitrification for epididymal spermatozoa without cryoprotectants / 中华男科学杂志

<p><b>OBJECTIVE</b>To explore the feasibility and safety of microdrop-vitrification for epididymal spermatozoa obtained by percutaneous epididymal sperm aspiration (PESA) without cryoprotectants.</p><p><b>METHODS</b>We treated the epididymal sperm samples from 22 patients by conventional freezing (Group 1) and microdrop-vitrification without cryoprotectants (Group 2), and evaluated the effectiveness of the two methods by comparing their revival rate, retrieval rate and incidence of sperm nuclear DNA fractures.</p><p><b>RESULTS</b>Motile sperm were found in all but 1 case in Group 1. The revival rates of the frozen sperm were low in both Groups 1 and 2 ([18.16 +/- 9.38]% vs [21.99 +/- 10.95]%, P > 0.05), but statistically significant differences were shown between the two groups in the retrieval rate ([58.39 +/- 12.67]% vs [70.82 +/- 14.94]%, P < 0.01). Before freezing, nuclear DNA fractures existed in the epididymal sperm samples of all the 22 patients, comet sperm were seen after unicellular gel electrophoresis, and the incidence of sperm nuclear DNA fracture was (26.68 +/- 9.45)%. After freezing, no increase was observed in the incidence of sperm nuclear DNA fracture in either Group 1 or 2 ([28.68 +/- 12.54]% vs [27.64 +/- 10.70]%, P > 0.05).</p><p><b>CONCLUSION</b>Microdrop can be used as a suitable freezing carrier for a low number of sperm, and cryoprotectant-free vitrification with microdrop may be a simple, safe and effective method for the cryopreservation of a low number of epididymal sperm.</p>

Nuclear status of day 2 preembryos affects embryo quality and implantation potential / 中华男科学杂志

<p><b>OBJECTIVE</b>To assess the effects of the nuclear status of day 2 preembryos on day 3 embryo quality and implantation potential and to weigh its clinical value in the human in-vitro fertilization-embryo transfer (IVF-ET) program.</p><p><b>METHODS</b>Embryos obtained from 409 fresh conventional IVF-ET/ICSI cycles from July to October 2006 were assessed retrospectively. Day 2 preembryos were classified according to the number of nuclei in each blastomere in 3 groups: grade A with only mononucleated blastomeres, grade B with one or more blastomeres containing no visible nucleus, and grade C with one or more multinucleated blastomeres. Comparisons were made of the rates of arrested embryos and excellent embryos on day 3 as well as of the pregnancy outcome and implantation potential of those in whom cohorts of similar nuclear scoring embryos were transferred.</p><p><b>RESULTS</b>There were fewer arrested embryos and more excellent embryos on day 3 in grade A than in grade B and C (P < 0.01), and so were there in grade B than in grade C (P < 0.01). Among the 234 cycles in which all the transfer embryos were derived from a similar day 2 nuclear scoring, 51 cycles originated from grade A embryos (group A) and 183 from grade B (group B), with similar clinical pregnancy rates between the two groups, while the implantation rate was higher in group A than in B (P < 0.05).</p><p><b>CONCLUSION</b>Day 2 nuclear scoring can be used to predict the devel- opment and implantation potential of embryos. A combined evaluation of day 2 nuclear scoring and day 3 embryo morphology helps identify the most viable embryos and reduce the number of embryos for transfer.</p>

Cryopreservation by cryoloop damages human immature oocytes / 中华男科学杂志

<p><b>OBJECTIVE</b>To examine the influence of cryoloop on the spindle and chromosome configurations of human oocytes cryopreserved in the germinal vesicle (GV) and metaphase II (M II) stages, as well as on the survival rate and potential for in vitro maturation (IVM).</p><p><b>METHODS</b>GV oocytes were randomly assigned into a control group (matured in vitro into the M II stage), a GV cryopreserved group (cryopreserved in the GV stage and then matured in vitro), and an M II cryopreserved group (matured in vitro and cryopreserved in the M II stage). After cryopreservation and IVM, immunostaining of the tubulin and chromatin was performed followed by visualization using laser scanning confocal microscopy (LSCM).</p><p><b>RESULTS</b>A significantly higher survival rate was observed in the GV cryopreserved group than in the M II , but the maturation rate showed no significant difference between the GV cryopreserved group and the control (P > 0.05). Compared with the control group, there was a statistically significant decrease in the rates of normal meiotic spindles and chromosomes in the GV cryopreserved group (P < 0.05). A significantly lower rate of normal spindles was noted in the M II cryopreserved group than in the control, but no statistical difference was shown in the rate of normal meiotic chromosomes between the two groups (P > 0.05).</p><p><b>CONCLUSION</b>Cryopreservation by cryoloop has a damaging effect on the spindle and chromosome of human oocytes in the GV and M II stages.</p>

Comparison between the results of ICSI with fresh and with frozen-thawed sperm obtained by PESA to treat azoospermia / 中华男科学杂志

<p><b>OBJECTIVE</b>Retrospective study of the results of ICSI (intracytoplasmic sperm insemination) with frozen sperm obtained by PESA (percutaneous epididymal sperm aspiration) was performed in 27 patients.</p><p><b>METHODS</b>With conventional freezing method, sperm from diagnosing PESA and the remaining motile sperm after treating cycle were frozen. After frozen-thawed and ICSI process, fertilization rate, implantation rate, clinical pregnancy rate were compared and other outcomes including pregnant combinations and parameters of newborns of experimental group (which used frozen-thawed sperm) and control group (which used fresh PESA sperm) were analyzed respectively.</p><p><b>RESULTS</b>One hundred and sixty three and 1 157 oocytes of stage M II were injected respectively in the experimental group (15 cycles) and control group (100 cycles), and fertilization rate of experimental group was prominently higher than that of control group (84.05% vs 73.29%, P < 0.05), while implantation rate and clinical pregnancy rate were of no difference from the control, respectively (23.07% vs 15.73%; 53.33% vs 37.00%, P > 0.05). The differences in newborn's weights between two groups were of no statistical significance (P > 0.05). In the experimental group, eight clinical pregnancies were achieved including 5 live deliveries and 3 ongoing pregnancies, 37 clinical pregnancies including 30 deliveries with only 1 fetal death, 3 ongoing pregnancies and 4 abortions in the control group. Neither vital pregnant combinations nor neonate malformations were found in both groups.</p><p><b>CONCLUSION</b>ICSI using frozen-thawed sperm obtained by PESA is an economic effective and safe method to treat azoospermia. Recovering rates of frozen sperm form PESA should be further increased.</p>

Effects of simulated microgravity on L-ARG-NO-CGMP pathway of abdominal aorta in rats / 中国应用生理学杂志

<p><b>AIM</b>To investigate the effects of simulated microgravity on dilatory responsiveness and NOS expression of abdominal aorta in rats.</p><p><b>METHODS</b>Twenty male healthy SD rats, which body weight ranged from 300 g to 330 g, were divided into control group and simulated microgravity group randomly. After 4 weeks, using isolated arterial rings from rats, arterial dilatory responsiveness of abdominal aorta were examined in vitro. And the expression of nitric oxide synthase (NOS), including endothelial NOS (eNOS) and inducible NOS (iNOS), were observed by Western blot.</p><p><b>RESULTS</b>Dilatory responses of arterial rings to L-Arginine (10(-8)-10(-3) mol/L), and Acetylcholine mol/L) were decreased in simulated microgravity rats compared with that of controls; but dilatory responses of isolated aortic rings to sodium nitroprusside (mol/L) and 8-bromo-cGMP(mol/L) were similar in both simulated microgravity rats and control rats. The expression of both eNOS and iNOS had not showed significant differences between two groups.</p><p><b>CONCLUSION</b>The data indicate that endothelium dependent vasorelaxation in abdominal aortic rings are decreased by 4-week simulated microgravity, and this change may be result from altered NOS activity in endothelium.</p>