血小板活化因子對小白鼠精子活性之影響

Abstract

在哺乳類的生殖上，精子的活性調控扮演著重要的角色。射精後的精子在跟卵子發生反應前，必須經歷相當長的旅行以及大量的修飾，才能完成此目標。而精子如何得到令卵受精的能力，即稱為獲能作用（capacitation）。尋找那些跟精子獲能作用有關連的分子，則是一個重要且必須具備的，因為在發生獲能作用後，精子才能進行頂體反應（acrosome reaction），以穿透卵外層之透明帶，到達卵子以進行受精。到目前為止，已被證實跟獲能作用有相關的事件有：精子細胞膜上脂質之改變、精子的超活動力、精子內鈣離子的增加以及tyrosine磷酸化的增加。 血小板活化因子是一個多功能的因子，在身體的各器官以及部位都會有作用。本研究即針對血小板活化因子對於精子所造成的影響。在利用CTC染色後，我同樣確定它會增加精子的獲能作用，並且增加精子的活動力。對血小板活化因子代謝方面，我在數個雄性生殖系統的器官內找到生產及分解它的酵素。另外我還偵測它對精子內膽固醇含量的影響，發現膽固醇會上升，而膽固醇酯會下降。還有在加入血小板活化因子後，精子內蛋白質的tyrosine磷酸化會些微的減少。而後面兩個結果是跟前人的研究相反的。

Regulation of sperm activity plays an important role in mammalian reproduction. Ejaculated sperm take a long journey and undergo a lot of modification before sperm-egg encounter. How sperm acquire the ability to fertilize an egg is generally termed capacitation . Finding the molecular events associated with the sperm capacitation is a prerequisite in order to unravel the molecular mechanism underlying the acrosome reaction that is essential during the penetration of sperm to zona pellucida of egg. As yet the capacitation-related events, including the rearrangement of plasma membrane lipid, hyperactivated motility, intracellular Ca2+ elevation and protein tyrosine phosphorylation, have been reported. Platelat-activation factor is a multifunctional factor. PAF shows profound effect on versatile cells. This study concerns the effect of PAF on the sperm activity. I found that PAF was able to enhance sperm motility and to promote sperm capacitation. Meanwhile, I also found that cholesterol content of sperm increased and tyrosine phosphorylation reduced after PAF treatment. This is controversial to the previous study that efflux of cholesterol took place and tyrosine phophorylation enhanced after capacitation.