Comparison of embryonic development in cleavage stage mouse embryo biopsy between acid Tyrode's solution and laser assisted techniques.

The study was carried out to determine the effectiveness and safety of the infrared 1.48 microm laser in cleavage stage mouse embryo biopsy, compared to the conventional acid Tyrode's solution. One hundred and thirty cryopreserved cleavage stage mouse embryos were included in the study. Fifty embryos were biopsied by acid Tyrode's solution. Forty-seven embryos were biopsied by the infrared 1.48 microm laser. Thirty-three embryos were incubated without biopsy as the control group. Thirteen of 50 embryos in the acid Tyrode's group and 16 of 47 in the laser assisted group became cavitating morulae on day 4, meanwhile 23 of 33 in the control group reached this stage. The blastocyst formation of acid Tyrode's, laser assisted and control group were 94.0, 97.8 and 100.0 per cent, respectively. The hatching rate of acid Tyrode's solution, laser assisted and control group were 78.7, 84.7 and 63.6 per cent, respectively. No significant difference in blastocyst formation and hatching rate was found. The percentage of grade I blastocysts in control group (96.9%) was significantly higher than those in acid Tyrode's solution (68.0%) and the laser assisted group (76.0%). There was no significant difference in the percentage of grade 1 blastocysts between the acid Tyrode's solution and the laser assisted group. In conclusion, the infrared 1.48 microm wavelength laser may be an alternative to acid Tyrode's solution in embryo biopsy.

Effect of nimodipine on male reproductive functions in rats.

Nimodipine, a dihydropyridine calcium channel blocker, was administered orally using two different doses (40 mg and 60 mg/kg/day) to rats. Both short term (2 weeks) and long term (6 weeks) effects of the drug were observed. The drug administration resulted in a marked decrease in sperm density, sperm motility and acrozomal reaction. Zona-pellucida penetration by the sperm obtained from drug-treated animals was significantly lower when compared with sperm from normal animals. Nimodipine stimulated Ca2+ ATPase activity in isolated plasma membrane of rate spermatozoa. In conclusion, short term and long term administration of nimodipine has deleterious effect on male reproductive functions in rats.

Intactness of zona pellucida does not affect the secretion of a trypsin-like protease from mouse blastocyst

Assisted hatching (AH), which is known to improve the hatching potential of mammalian embryos, has been used to increase the pregnancy rate in in vitro fertilization cycles. However, the effect of AH on a trypsin-like protease, which is known to be associated with the hatching process, has not been studied. In this study, we evaluate whether the intactness of zona pellucida affects the secretion of a trypsin-like protease from mouse blastocyst. Four- to 8-cell stage mouse embryos were collected at 66- to 68 hr after hCG injection and divided into 3 groups according to the manipulation of zona pellucida. The groups are no treatment (control), drilling of zona pellucida (ZD) and thinning of zona pellucida (ZT). The activity of a trypsin-like protease, blastocyst development and hatching rate were compared among the three groups at 110 and 135 hr after hCG injection, respectively. The protease activity and blastocyst development were not significantly different among control, ZD and ZT groups at 110 and 135 hr after hCG injection, respectively. However, the hatching rate of ZD and ZT groups was significantly higher than that of control group at each time, respectively (p>0.001). Even in the zona pellucida removed embryos, the protease activity did not differ from the control group. In conclusion, the secretion of a trypsin-like protease from mouse blastocyst does not seem to be affected by the intactness of zona pellucida.