Tag Archives: rat heart mitochondria

Oxidative stress in rat heart mitochondria under a rotenone model of Parkinson’ disease: a corrective effect of capicor treatment

O. O. Gonchar*, O. O. Klymenko, T. I. Drevytska,
L. V. Bratus, I. M. Mankovska

Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, Kyiv;
*e-mail: olga.gonchar@i.ua

Received: 22 March 2021; Accepted: 22 September 2021

Biochemical and genetic mechanisms of oxidative stress (OS) developing in rat heart mitochondria were studied in a rotenone model of Parkinson’s disease (PD), and the effect of Capicor (combination of meldonium dihydrate and gamma-butyrobetain dihydrate) on these mechanisms was evaluated. Experiments  were carried out on adult male Wistar rats: I – intact rats (control); II –with rotenone administration subcutaneously at dose 3 mg/kg per day along 2 weeks; III – with rotenone/Capicor administration: after rotenone intoxication, capicor was injected intraperitoneally at dose 50 mg/kg per day along following 2 weeks. As OS biomarkers, lipid peroxidation, protein oxidative modification, H2O2 production, the activity of MnSOD, GPx and glutathione pool indexes were measured. The PD-related genes Parkin (PARK2) and DJ-1 (PARK7) as well as MnSOD and DJ-1 protein expressions were detected. Rotenone intoxication increased the intensity of lipid peroxidation, protein oxidative modification, and H2O2 production. These events were accompanied by decreased in GSH content, GSH/GSSG ratio, and GPx activity. Increased ROS production and impaired antioxidant defenses could result from the established DJ-1 gene and DJ-1 protein deficiency. Capicor administration increased  the endogenous antioxidant defense, weakening the lipid peroxidation and oxidative modification of mitochondrial proteins. Capicor treatment led to an increase in GSH content and GSH/GSSG ratio in heart mitochondria that may serve as additional indicators of the OS intensity reducing. Capicor promoted overexpression of DJ-1 and PARK2 genes in the heart that may indicate a rise in mitophagy and a decrease in OS.

Influence of Tl(+) on the Ca(2+) and Na(+) movement across rat neonatal cardiomyocytes and rat heart mitochondria membranes

S. M. Korotkov, V. P. Nesterov, G. B. Belostotskaya,
I. V. Brailovskaya, A. V. Novozhilov, C. V. Sobol

Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russian Federation;
e-mail: korotkov@SK1645.spb.edu

Received: 05 September 2019; Accepted: 29 November 2019

Thallium is known to produce one of the most complex and serious patterns of toxicity, involving a wide range of human organs and tissues. The toxic impact on biologic organisms is linked especially to the ability of Tl+ to disturb calcium homeostasis and  to permeate easily the inner mitochondrial membrane (IMM). The aim of this work was to study the effects of Tl+ on intracellular Ca2+ dynamics in rat neonatal cardiomyocytes as well as on sodium penetrability of the IMM and Tl+-induced mitochondrial permeability transition pore (MPTP) opening in isolated Ca2+-loaded rat heart mitochondria (RHM). The use of the fluorescent calcium indicator Fura 2 AM showed that Tl+ induced calcium influx across the plasmatic membrane, resulting­ in calcium ([Ca2+]i) increase in the cytoplasm. This increase was even more pronounced in experiments with accelerating of Tl+-transmembrane fluxes by nonactin. It was nevertheless abolished by the removal of extracellular Ca2+ ions, but was not inhibited by a calcium-channel blocker (nifedipine). Tl+ did not release calcium from the intracellular stores. Tl+ potentiated sodium permeability of the IMM because swelling of nonenergized RHM in medium containing TlNO3 and NaNO3 was enhanced at high Tl+ concentration. The calcium load of RHM induced MPTP opening which was accompanied by the increase of the swelling as well as the decrease of  the inner membrane potential and of state 40 (basal) and state 3UDNP (2,4-dinitrophenol-uncoupled) respiration. These effects of Tl+ were suppressed by MPTP inhibitors (cyclosporine A, ADP and n-ethylmaleimide). The data obtained showed that Tl+-stimulated influx of extracellular calcium into cardiomyocytes could cause calcium and sodium RHM overload, which lead to the MPTP opening, thus determining the sensitivity of heart muscle to thallium intoxication.