细胞内游离钙的减少与人类精子运动

Serres C, Feneux D, Berthon B

Laboratoire de Biologie de la Reproduction et du Développement, Histologie, Embryologie, Cytogénétique, Centre Hospitalier, Kremlin-Bicêtre, France.

Cell Motil Cytoskeleton. 1991;18(3):228-40. doi: 10.1002/cm.970180308.

In order to elucidate the effects of calcium on the movement of human spermatozoa, studies were conducted using motile cells selected by swim-up migration at 37 degrees C in 5% CO2 in air in a synthetic BWW medium containing 1.7 x 10(-3) M CaCl2 or BWW without added calcium (BWW-Ca). Preliminary experiments have confirmed that the addition of EGTA (5 x 10(-3); 10(-2) M) to BWW medium decreased the intracellular calcium concentration ((Ca++)i) of spermatozoa, as measured in cells loaded with a fluorescent Ca++ indicator, Quin-2. Concomitant measurements of (Ca++)i and sperm movement (analysed by videomicrography at 200 f/s at room temperature) were carried out on Quin-2 loaded cells incubated in BWW-Ca medium plus EGTA (10(-5) M; 10(-4) M; 10(-3) M). Under these conditions a decrease in (Ca++)i was observed and associated with a decrease in mean amplitude of lateral head displacement (ALH). Analysis using an automatic analyser (Hamilton Thorn at 37 degrees C) confirmed these results: the percentage of spermatozoa swimming with ALH greater than or equal to 6 microns is decreased when the external free calcium in BWW-Ca is decreased by the addition of 10(-5) M, 10(-4) M, or 10(-3) M EGTA. Flagellar analysis of the sperm population characterized by ALH greater than or equal to 6 microns showed a large proximal curvature of the tail associated with a low propagation wave velocity and a low beat frequency as compared to the spermatozoa with ALH less than 6 microns with similar progressive velocities. These characteristics result in a high flagellar beat efficiency (in terms of head displacement per beat). The disappearance of this pattern of movement when intracellular calcium is lowered indicates that calcium plays a complex role in the relationship between curvature and wave propagation. The ability of spermatozoa to modulate their movement in response to an alteration in the intracellular calcium level confirms the role of calcium in controlling flagellar movement in intact cells.

为了阐明钙对人类精子运动的影响，研究人员在含有1.7×10⁻³ M氯化钙的合成BWW培养基或无添加钙的BWW（BWW-Ca）中，于37℃、5%二氧化碳的空气中，通过上浮迁移选择活动细胞进行了相关研究。初步实验已证实，向BWW培养基中添加EGTA（5×10⁻³；10⁻² M）可降低精子的细胞内钙浓度（[Ca²⁺]i），这是在加载荧光钙指示剂Quin-2的细胞中测量得到的。对在BWW-Ca培养基加EGTA（10⁻⁵ M；10⁻⁴ M；10⁻³ M）中孵育的加载Quin-2的细胞，同时进行了[Ca²⁺]i和精子运动（在室温下以200帧/秒通过视频显微镜分析）的测量。在这些条件下，观察到[Ca²⁺]i降低，并与头部侧向位移平均幅度（ALH）降低相关。使用自动分析仪（37℃的Hamilton Thorn）进行的分析证实了这些结果：当通过添加10⁻⁵ M、10⁻⁴ M或10⁻³ M EGTA降低BWW-Ca中的细胞外游离钙时，ALH大于或等于6微米的游动精子百分比降低。对以ALH大于或等于6微米为特征的精子群体进行鞭毛分析表明，与具有相似前进速度但ALH小于6微米的精子相比，尾部近端有较大弯曲，同时传播波速度较低且拍频较低。这些特征导致鞭毛拍频效率较高（就每次拍动时的头部位移而言）。当细胞内钙降低时这种运动模式消失，表明钙在曲率与波传播之间的关系中起复杂作用。精子响应细胞内钙水平变化调节其运动的能力证实了钙在完整细胞中控制鞭毛运动的作用。