Methods for dynamic and whole volume imaging of the zebrafish heart.

Tissue development and regeneration are dynamic processes involving complex cell migration and cell-cell interactions. We have developed a protocol for complementary time-lapse and three-dimensional (3D) imaging of tissue for developmental and regeneration studies which we apply here to the zebrafish cardiac vasculature. 3D imaging of fixed specimens is used to first define the subject at high resolution then live imaging captures how it changes dynamically. Hearts from adult and juvenile zebrafish are extracted and cleaned in preparation for the different imaging modalities. For whole-mount 3D confocal imaging, single or multiple hearts with native fluorescence or immuno-labeling are prepared for stabilization or clearing, and then imaged. For live imaging, hearts are placed in a prefabricated fluidic device and set on a temperature-controlled microscope for culture and imaging over several days. This protocol allows complete visualization of morphogenic processes in a 3D context and provides the ability to follow cell behaviors to complement in vivo and fixed tissue studies. This culture and imaging protocol can be applied to different cell and tissue types. Here, we have used it to observe zebrafish coronary vasculature and the migration of coronary endothelial cells during heart regeneration.

Neonatal intestinal injury induced by maternal separation: pathogenesis and pharmacological targets 1.

Maternal separation (MS) is a well-studied phenomenon thought to play a role in the pathogenesis of many diseases ranging from neuropsychiatric to early intestinal disorders such as necrotizing enterocolitis. The existing evidence suggests that MS initiates a variety of processes that in turn lead to early intestinal injury. Although there are many theories as to how MS alters normal physiological processes, the exact mechanism of action remains to be elucidated. This review aims to describe some of the pathological processes affecting the intestine that are caused by MS, including (i) brain-gut axis, (ii) intestinal epithelial barrier function, (iii) microbiome, (iv) oxidative stress and endoplasmic reticulum stress, and (v) gut inflammation.