Abstract
Using our recently developed laser speckle contrast imaging (LSCI) to visualize blood vessels and monitor blood flow, here we test the utility of the chick embryo for drug screening. To this end, we examined the effects of antihypertensive agents Nifedipine and Amlodipine, belonging to the L-type calcium channel antagonist family, on blood flow visualized noninvasively through the intact shell. Guided by the live view mode, the drugs were injected through the shell and ventral to HH16-19 chick embryos. Our results show a significant reduction in the chick heart rate, blood flow, and vascular size within 5-20 minutes after Nifedipine or Amlodipine injection. For moderate Nifedipine concentrations, these parameters returned to initial values within 2-3 hours. In contrast, Amlodipine showed a rapid reduction in heart rate and blood flow dynamics at a more than ten times higher concentration than Nifedipine. These findings show that our LSCI system can monitor and distinguish the chick heart’s response to injected drugs from the same family. This serves as proof-of-concept, paving the way for a rapid, cost effective, and quantitative test system for screening drugs that affect the cardiovascular system of live chick embryos. Live noninvasive imaging may also provide insights into the development and functioning of the vertebrate heart.
Highlights
Non-invasive Laser Speckle Contrast Imaging (LSCI) of the chick chorioallantoic membrane (CAM) in whole incubated eggs
Simultaneous recording images of the CAM, dynamics of blood flow, and heart rate
Live view mode to identify size, heart position, and location of the embryo in the egg
Automated system for data acquisition and analysis
Longitudinal quantification of the impact of a calcium channel antagonists, nifedipidine and amlodipine on the embryonic heart rate, CAM’s blood flow, size and number of vessels
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
↵* e-mails: readhead{at}caltech.edu, sim.mahler{at}gmail.com
