The Development of Early Mouse Embryos Depend on Ca2+ Concentration.

Yang,  Jung Sook; Bae,  In Ha

Original Article

Korean Journal of Fertility and Sterility 2000;27(3):275-282.
Published online January 1, 2001.

The Development of Early Mouse Embryos Depend on Ca2+ Concentration.

Abstract

OBJECTIVE
This study was to determine the effect of different concentration of calcium in medium on the preimplantational development of zygotes and early 2-cell embryos. METHODS: Female mice of ICR strain (5~8 weeks old) were superovulated and mated with fertile males. Zygotes or early 2-cell embryos were collected by flushing the oviducts 31~32 hours after hCG injection. The embryos were cultured in various concentrations of Ca2+ in medium or with EDTA, EGTA and Ni2+. RESULT AND CONCLUSION: Treatment of high concentration of Ca2+ (3.42 mM (2X)~17.1 mM (10X) in medium didn't develop well compared to the control Low concentrations of Ca2+ (0.214 mM (1/8X)~0.855 mM (1/2X)) were deterimental to development beyond 2-cell stage. EDTA, Ca2+ chelating agent was treated with ranged concentrations of eDTA (0.014 mM~0.107 mM) to medium contaning 1.71 mM Ca2+ showed beneficial effect to development to blastocyst compared to the control. EGTA, extracellular Ca2+ chelator, was treated with ranged concentrations of EGTA (0.014~0.107 mM) to the medium contaning 1.71 mM Ca2+. There is no significant difference with the control. Ni2+ (50 micrometer), T-type Ca2+-channel blocker was treated to medium contaning low concentration of Ca2+. It overcame 2-cell block significantly. Rate of degenerated embryos decreased and developmental rate to morula and blastocyst increased more than low Ca2+ concentration alone. Further studies are needed for the overcoming effect of 2-cell block by Ni2+.