Endogenous Protective Mechanisms in Remodeling of Rat Heart Mitochondrial Membranes in the Acute Phase of Streptozotocin-Induced Diabetes

摘要

The aim of present study was to investigate functional andphysical alterations in membranes of heart mitochondria that areassociated with remodeling of these organelles in acute phase ofstreptozotocin-induced diabetes and to elucidate the role of thesechanges in adaptation of the heart to acute streptozotocin-induced diabetes (evaluated 8 days after single dosestreptozotocin application to male Wistar rats). Action of freeradicals on the respiratory chain of diabetic-heart mitochondriawas manifested by 17 % increase (p<0.05) in oxidized form ofthe coenzyme Q_(10)and resulted in a decrease of states S3 andS4respiration, the respiratory control index, rate of phosphorylation(all p<0.01) and the mitochondrial transmembrane potential(p<0.05), but the ADP/O ratio decreased only moderately(p>0.05). On the contrary, membrane fluidity and the totalmitochondrial Mg~(2+)-ATPase activity increased (both p<0.05). Indiabetic heart mitochondria, linear regression analysis revealed areciprocal relationship between the increase in membrane fluidityand decrease in trans-membrane potential (p<0.05, r = 0.67).Changes in membrane fluidity, transmembrane potential, Mg~(2+)-ATPase activity and the almost preserved ADP/O ratio appear asthe manifestation of endogenous protective mechanismsparticipating in the functional remodeling of mitochondria whichcontributes to adaptation of the heart to diabetes.