Effects of hypergravity on Xenopus embryo growth and cardiac hypertrophy

All life on earth has developed and evolved in a 1G environment. Therefore, any deviation below or above unit gravity will likely have an effect on the development of organisms, including the migration of cells and the dispersion of nutrients. The purpose of this research project is to analyze the effects of hypergravity on the overall body length and cardiac growth of Xenopus laevis embryos. I predict that cardiac hypertrophy will occur in embryos subjected to hypergravity because of the increased force required from the heart to adequately circulate blood and, thus, disperse nutrients. Upon reaching early gastrulation, embryos were exposed to a 7G, achieved via centrifugation, or a 1G (control) setting for an additional 96 hours. I recorded mortality rates, and body length measurements were taken on all living embryos. I found that differences in mortality between the groups were not significant but that body length was significantly reduced by an average of 6.8% in the 7G group. Subsequently I sectioned the embryos and measured the diameter and area of the cardiac tissue using image analysis software. I found the 7G group had a significantly smaller average body area (reduced by an average of 18%) and a significantly larger ventricular area (enlarged by an average of 36%) when compared to the 1G (control) group. The ventricle area to average body area ratio was found to be significantly larger in the 7G group (ratio value of 0.054) when compared to the 1G group (ratio value of 0.034). From these data, I conclude that hypergravity has a significant inhibitory impact on the Xenopus laevis embryo growth and causes a significant increase in ventricular cross-sectional area