Morphometry of mitochondrial changes in mouse trophoblast cells at early implantation.

The blastocysts of a mouse in an experimentally delayed implantation are known to have a low consumption of oxygen, but when implantation is initiated their oxygen consumption increases within 4 h. Our stereological analyses of the mitochondria have demonstrated that these changes are associated with an increase in volume density of the mitochondrial matrix and a decrease of surface density of the inner membranes. Thus, at this early stage of blastocyst implantation, the mitochondria of the activated blastocysts change to an orthodox state.