Calcium Phenotyping and Ionophores in mus musculus Sperm

Abstract

Sperm capacitation is the process of maturation of a sperm cell for fertilization, defined by several key events. Capacitated sperm display a hyperactive motility state and release their acrosomal vesicles. These changes promote the ability of an individual sperm cell to find and fuse with the egg. Currently, the intracellular changes that occur during capacitation are poorly understood. However, it is known that calcium ion and bicarbonate concentration in the environment are key signaling molecules that effect change. Calcium and bicarbonate are transported into the cell by several membrane transport proteins, including the testis-specific CatSper and a Ca2+/HCO3- cotransporter. Here, we examine changing intracellular calcium concentrations in response to environmental conditions using spectral plate assays and flow cytometry in order to further our understanding of the capacitation signal mechanism. Indo-1 dye was used to fluorescently measure intracellular calcium in response to the ionophores ionomycin and A23187.