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Modification of expression of several genes encoding enzymes involved in radical production and DNA repair by a 1,4-DHP derivative glutapyrone was studied in intact rats and animals with streptozotocin diabetes mellitus. Glutapyrone stimulated iNos mRNA production in both kidneys and blood. The effect was stronger in kidneys of diabetic animals, however in blood the expression was down-regulated. The compound increased the Parp 1 gene expression in kidneys of both intact and diabetic animals; in blood the effect was adverse. Expression of XDh gene was significantly increased by glutapyrone in kidneys of intact and diabetic animals. Administration of the compound to intact animals triggered significant increase of DNA damage in white blood cells assayed by comet assay; in diabetic animals no effect was produced. To explain discrepancies with the formerly described effects of glutapyrone on cultured cells, metabolism of the compound was studied. Glutapyrone is either oxidised or the residue of glutamic acid is removed, glutapyrone turns into AV-153, and the latter is metabolised to smaller compounds. Formation of AV-153, a DNA binder and genotoxic compound in high concentrations, can explain DNA damage in white blood cells and stimulation of DNA repair. [ABSTRACT FROM AUTHOR]

Diabetic cardiomyopathy increases the risk of heart failure and worsens prognosis for diabetes mellitus (DM) patients. Its development depends on many factors, including modification of nitric oxide production and impaired DNA repair. The goal of the present work was to study in vivo effects of a 1,4-dihydropyridine AV-153, known as antimutagen and DNA-binder, on DNA integrity, and on the expression of several proteins involved in glucose transport, nitric oxide metabolism, and DNA repair in myocardium in diabetic rats. DM was induced in rats by streptozotocin (STZ) injection. Expression of proteins was studied by means of immunohistochemistry. Development of the STZ-induced DM significantly induced PARP1 and gamma H2AX histone, markers of DNA breakage, protein expression in heart tissue, while AV-153 administration decreased PARP1 and H2AX protein expression. In this model of diabetes, myocardial expression of iNOS was also significantly increased, but administration of AV-153 reduced it to normal levels. AV-153 also upregulated the expression of insulin-dependent GLUT4 and insulin-independent GLUT1 glucose transporters up to normal level in diabetic rats. Thus, AV-153 appears to be prospective for creation of a remedy for prevention of diabetic cardiomyopathy. [ABSTRACT FROM AUTHOR]