2D finite-element analysis of calcium distribution in oocytes

Abstract

Oocyte and egg provide an excellent model system for studying calcium patterns. Calcium signal is a transient increase of intracellular calcium concentration which influences different cellular processes among a variety of different cells. The change in calcium concentration transmits information through an organized set of spatio-temporal changes, localized transients or puffs, calcium wave propagation, and global oscillations. During oocyte maturation, the calcium signalling machinery undergoes differentiation which results in distinctly different calcium release patterns on all organizational scales from puffs to waves. It is crucial to understand the mechanics of calcium regulation in cytosol of oocytes, to have better understanding of fertilization process. In this paper, a finite-element model using coaxial circular sector elements has been developed to study two-dimensional calcium distribution in oocytes. Appropriate initial and boundary conditions are incorporated in the model based on biophysical conditions of the problem. A computer program has been developed in MATLAB 7.10 for the whole problem and executed on Intel(R) Core™ i3 CPU, 4.00 GB RAM, 2.40 GHz processor to obtain numerical results. These results have been used to study the relationship of calcium concentration with parameters like Na+/Ca2+ exchanger, Na+/K+ pump, RyR calcium channel, SERCA pump, and buffers. It is observed that there is significant variation in calcium profiles due to the effect of Na+/Ca2+ exchanger, Na+/K+ pump, RyR calcium channel, SERCA pump, and buffers. The results give us the better insights of coordinated effect of Na+/Ca2+ exchanger, Na+/K+ pump, RyR calcium channel, SERCA pump, and buffers on calcium distribution in oocytes.