Carbohydrate Metabolism in Diabetic Rat’s Heart – The Effects of Acetylsalicylic Acid and Heat Preconditioning as HSP70 Inducers

Abstract

Abstract The myocardium of diabetic subjects displays reduced HSP70 protein level and weak myocardial protection. However, the heart possesses an ability to produce heat shock proteins (HSPs) after exposure to sublethal heat stress. Acetylsalicylicacid (ASA) has the property of pharmacological induction of HSPs. We evaluated the common effects of single dose ASA-pretreatment, prior to heat preconditioning (HP), over carbohydrate metabolism-related enzymes and substrates in the heart of diabetic rats. Streptozotocin-diabetes caused significant decrease of HSP70 protein level, stimulation of the gluconeogenic processes and inhibition of glycolytic processes in the heart. HP-diabetic hearts have significantly higher HSP70 protein level, lower glycogen, glucose-6-phosphate content, glycogen phosphorylase and hexokinase activity, and higher glucose levels and PFK activity. ASA-pretreatment of HP-diabetic animals caused additional increase of HSP70, additional decrease of glycogen, glucose-6-phosphate, glycogen phosphorylase and hexokinase, and additional increase of glucose and PFK in the heart. In conclusion, HP is physiological inducer of HSP70 level in heart and tends to reverse carbohydrate - related disturbances in diabetic rats. ASA, given prior to HP, is a potent HSP70 co-inducer and causes additional increase of HSP70 protein level in heart. ASA, given in a combination to HP, have shown more evident protective effects against subsequent intense of stress.