Next time you are cursing your yard for having to prune your bushes, just take a cold sip of lemonade and know that you are helping your shrubs thrive. Or, you are just making them all look like green meatballs, like my shrubs. Win-win! Pruning is an essential part of development, and a recent paper shows pruning of the vasculature in the developing zebrafish brain.
Our brains are surrounded by a complex network of blood vessels that deliver oxygen and nutrients to the neurons. Although the existence of this vasculature has long been appreciated and studied, it has not been clear how the network is formed during development. A recent paper uses confocal live imaging to track the development of the vessel network in the developing zebrafish midbrain. Chen and colleagues found that the zebrafish brain undergoes both blood vessel growth and pruning during development. Blood vessel pruning is driven by blood flow—decreased blood flow triggers pruning, while increased blood flow impairs pruning. In the images above, a segment of blood vessel from the midbrain vasculature undergoes pruning (red arrow).
Chen Q, Jiang L, Li C, Hu D, Bu JW, Cai D, & Du JL (2012). Haemodynamics-driven developmental pruning of brain vasculature in zebrafish. PLoS biology, 10 (8) PMID: 22904685