Effects Of Endotoxin On Capacitation And Acrosome Reaction Of Mouse, Golden Hamster And Human Sperm And On Sperm-oocyte Fusion And Embryo Development Of Mouse In Vitro

ObjectiveThe present study was to investigate the effects of endotoxin on capacitation and acrosome reaction (AR) of mouse, golden hamster and human sperm, on the sperm-oocyte fusion in mouse, and on the development of 1-cell, 2-cell and zona-free 2-cell mouse embryos in vitro. The purpose was to definite the committed step and the mechanism during in vitro fertilization (IVF) on which endotoxin affected, and to distinguish the sensitivities to endotoxin of three developmental systems of mouse embryos. All these data would provide the reference to clinical and laboratory quality control.Materials and MethodsThe mouse, golden hamster and human sperm were incubated with endotoxin in different concentration for different time to get capacitation, respectively, and AR was induced by progesterone after capacitation, then the rates of capacitation and AR were detected by chlortetracycline (CTC) and Hoechst 33258 fluorescent staining method. The medium was with endotoxin in different concentration in sperm-oocyte fusion step during IVF, then the fertilization rate was observed. The 1-cell, 2-cell and zona-free 2-cell mouse embryos were incubated in the medium with endotoxin, then the rate of blastocysts was recorded.Results1. Capacitation rate of mouse sperm in the control didn't change obviously during incubation (P>0.05), while the rate in 1.0μg/mL groups at 60min was higher than that of Omin(P<0.05), and the rates of capacitation in 0.1μg/mL and 1.0μg/mL groups significantly increased than that of the control at 60min (P<0.05).At 90min, the rates at the levels of 0.1μg/mL and 10.0μg/mL were lower than those of the control and 1.0μg/mL groups(P<0.05).2. Capacitation rate of golden hamster sperm in the control increased significantly at 6.5h(P<0.05), while the rate in 1.0μg/mL group at 5.5h was higher than that of 0min(P<0.05).3. Capacitation rate of human fresh sperm in the control didn't change obviously during incubation(P>0.05),but the rate of capacitation in 0.1μg/mL group at 7h increasedsignificantly than that at 0min(P<0.05).4. Capacitation rate of frozen-thaw human sperm in the control at 8h was higher than that at 0min(P<0.05), while in 10.0μg/mL group the rate of capacitation increased significantly at 6h(P<0.05).5. The AR rate of mouse sperm decreased with the rise of the endotoxin concentration, and the AR rate in 10.0μg/mL group was lower than those in the control and other groups (P<0.05). The AR rate of golden hamster sperm increased with the rise endotoxin concentration, and it got highest at 1.0μg/mL, then the rate started to decrease. The AR rate of human sperm at 10.0μg/mL was higher significantly than those of other groups (P<0.05).6. There was an obvious toxicity of endotoxin in sperm-oocyte fusion step, and it was in a dose-dependent manner. The fertilization rate in 0.1μg/mL group was lower than that of the control (P<0.05), and in l.Oug/mL group the rate decreased sharply (P<0.001).7. 1-cell mouse embryos were the most sensitive to endotoxin in the three developmental systems of mouse embryos, and there was a toxic effect with 1pg/mL (P<0.05), at the level of 5pg/mL, endotoxin affected on the three systems (P<0.05), and the toxic effect took place at the stage of 4-cell on zona-free 2-cell mouse embryos early. At the level of 10pg/mL, endotoxin affected on the development of 1-cell and 2-cell mouse embryos (P<0.05), while at the levels of 1pg/mL and 10pg/mL, there was not a significant toxicity on 2-cell mouse embryos (P>0.05).Conclusions1. Endotoxin made capacitation of mouse, golden hamster and human sperm increase in advance, and the effect on frozen-thaw human sperm was stronger than fresh human sperm.2. The effects of endotoxin on the AR rate which was induced by progesterone were different tendency to mouse, golden hamster and human sperm. The AR rate of mouse sperm decreased with endotoxin concentration increasing. The AR rate of golden hamster sperm was in a dose-dependent manner at fir...