Young R J, Bodt B A, Heitkamp D H
Life Sciences Department, Edgewood Research, Development and Engineering Center, Aberdeen Proving Ground, Maryland 21010-5423, USA.
Mol Reprod Dev. 1995 Jun;41(2):239-48. doi: 10.1002/mrd.1080410215.
An earlier study demonstrated that rabbit sperm incubated for 16 hr under capacitation conditions acquire motility patterns identical to those seen in rabbit sperm capacitated in vivo. We now show that similar motion patterns develop after 0.5 hr incubation in a Tris-buffered medium, medium M. Development and decline of the motion patterns occurred in three phases each recognized by the character of the biphasic motion patterns. Hyperactivated sperm were objectively identified and quantified by a previously developed computer-directed model. The percentage of motile sperm that acquired hyperactivated motility and the period they remained in this state varied among sperm from different rabbits. The decline in hyperactivated motility was paralleled by a decrease in the average sperm curvilinear velocity (VCL) and average amplitude of lateral head displacement (AALH), but was not accompanied by a concomitant decrease in percentage of motile sperm. Pb2+ and Cd2+, at concentrations that did not inhibit motility, prevented development of hyperactivated motility. Inhibition of hyperactivated motility by Pb2+ was time- and concentration-dependent; the average percentage of hyperactivated sperm decreased from approximately 30% to < 5% (n = 5) in 1 hr at a Pb2+ concentration of 25 microM. Cd2+ inhibition of hyperactivation was dependent only on concentration of the cation. At a concentration of 100 microM, the decrease in the percent of hyperactivated sperm was approximately 50% (n = 3). Hg2+, Zn2+, and Cr6+ at sublethal concentrations had no effect on hyperactivated motility development. These results suggest that Pb2+ and Cd2+, by virtue of their ability to prevent the wide curvature flagella beating that is characteristic of hyperactivation, can compromise fertilization at concentrations that do not inhibit sperm motility and act as a reproductive toxicant at a level other than spermatogenesis.
一项早期研究表明，在获能条件下孵育16小时的兔精子获得的运动模式与体内获能的兔精子相同。我们现在表明，在Tris缓冲液（培养基M）中孵育0.5小时后会出现类似的运动模式。运动模式的发展和衰退分为三个阶段，每个阶段都由双相运动模式的特征来识别。通过先前开发的计算机导向模型对超活化精子进行客观识别和定量。获得超活化运动能力的活动精子百分比以及它们保持这种状态的时间在不同兔子的精子中有所不同。超活化运动能力的下降与精子平均曲线速度（VCL）和头部侧向位移平均幅度（AALH）的降低同时发生，但活动精子百分比并未随之下降。Pb2+和Cd2+在不抑制运动能力的浓度下可阻止超活化运动能力的发展。Pb2+对超活化运动能力的抑制具有时间和浓度依赖性；在25 microM的Pb2+浓度下，1小时内超活化精子的平均百分比从约30%降至<5%（n = 5）。Cd2+对超活化的抑制仅取决于阳离子浓度。在100 microM的浓度下，超活化精子百分比的下降约为50%（n = 3）。亚致死浓度的Hg2+、Zn2+和Cr6+对超活化运动能力的发展没有影响。这些结果表明，Pb2+和Cd2+由于能够阻止超活化特有的宽曲率鞭毛摆动，在不抑制精子运动能力的浓度下会损害受精，并在精子发生以外的水平上作为生殖毒物起作用。
