The effect of Ni2+ on the intracellular Ca2+ increase of the mouse early 2-cell embryos / 대한불임학회지

ABSTRACT

OBJECTIVE: We reported the overcoming effect of Ni2+ on the in vitro 2-cell block of mouse embryos. In this study, we aim to investigate whether Ni2+ should induce intracellular Ca2+ transient in the mouse embryos. MATERIALS AND METHODS: Embryos were collected at post hCG 32hr from the oviduct of the ICR mouse and cultured in M2 medium omitted phenol red. Intracellular Ca2+ was checked by using a confocal laser scanning microscope and fluo-3AM by using various intracellular Ca2+ antagonists. RESULTS: In 1mM Ni2+ treated medium which contained Ca2+(1.71mM), 75.7% of the embryos showed [Ca2+]i transient about 200 sec later. In the Ca2+-free medium, 69.8% of the embryos showed [Ca2+]i transient. In U73122, phospholipaseC(PLC) inhibitor (5uM, 10min) pretreated group, 33.3% of the embryos showed [Ca2+]i transient. Heparine, inositol 1,4,5-triphosphate receptor(IP3R) antagonist preinjected embryos showed no response with 1mM Ni2+. In danthrolene treatment, ryanodine receptor(RyR)-antagonist, 43% embryos showed [Ca2+]i transient but they showed delayed response about 340sec in the presence of Ca2+. CONCLUSIONS: Summing up the above results, Ni2+ seems to induce Ca2+-release from the Ca2+-store even in the Ca2+-free medium. IP3 receptors of the mouse 2-cell embryos might have an essential role for the intracellular Ca2+ increase by Ni2+.