Effect of Cumulative Zinc Doses on Papillary Muscle Contractions and the Zinc Finger Protein ZEB1.

In this study, we aimed to investigate the effects of cumulative doses of Zn (by exposing samples to 1 µM, 10 µM, and 100 µM ZnCl) on myocardial papillary muscle contractions isolated from rat hearts in vitro and the roles of the zinc finger protein ZEB1 in this effect. In these preparations, 100 µM ZnCl application in different protocols caused a decrease in contraction force and an increase in contraction time in both frequency-dependent parameters and pre-expected stimuli when compared to the control group. Our study data show that Ca homeostasis is closely related to increasing Zn doses (especially at 100 µM ZnCl dose). Secondly, the levels of ZEB1, a zinc finger protein, were also significantly lower in the 100 µM ZnCl group compared to the other groups, which seems to be related to the increase in Ca that triggers ROS production at high doses of Zn. The data of our study, which we conducted to understand the Zn concentrations in the heart and to reveal new mechanisms that play a role in the regulation of Ca dynamics in heart tissue and is the first research in the literature on this subject, show that in vitro zinc application may have a dose-dependent effect on myocardial papillary muscle contractions.