In vivo imaging of the developing mouse embryonic vasculature

Live confocal microscopy of vital fluorescent markers, expressed in mouse embryonic tissues, is a powerful and exciting method to study mammalian embryonic development. This chapter discusses imaging approaches to visualize and characterize dynamic changes of the yolk-sac vasculature and blood flow in mouse embryos. We describe static embryo-culture protocols, which allow maintaining early mouse embryos on the imaging stage for over 24 h. We also describe vital fluorescent-reporter lineages, which can be used to image the developing vasculature and characterize hemodynamics by tracking individual blood cells. Imaging approaches described in this chapter can be used to analyze cardiovascular defects in mutant animals and can provide insights into understanding how genetic signaling pathways and physiological inputs regulate development.