Estudo dos marcadores de hipóxia e de estresse oxidativo em diferentes momentos da vida de ratas e em seus descendentes no quadro diabético

Abstract

The purpose of this study was to investigate hypoxia and oxidative stress markers in the blood and liver of diabetic rats and their offspring. Mild diabetes (D) was induced in the newborn rats using streptozotocin-STZ. Non-diabetic newborns (control-C) received the buffer. The newborn were distributed randomly into groups according to their euthanasia (5, 15, 30, 60, or 90 days of life). Female rats (C and D groups) were weighed and lethally anesthetized to obtain blood samples for measurement glucose and insulin levels, and evaluate oxidative stress markers (SOD, catalase, MDA, GSH-Px, and thiol groups) in washed erythrocytes and in the liver. A group of C and D adult rats were mated, and at term pregnancy washed erythrocytes and liver were sampled from the dams and their fetuses to evaluate the same markers before pregnancy. Another group of dams was also assembled to obtain offspring (Days 5 and Day 15 of life) to study same markers. The HIF-1α and PGC-1 gene and protein expression was analyzed in all experimental groups. There was higher glycemia on Days 5, 30, 90 in the life and pregnancy and lower insulin levels on Day 15, 60 and 90 of the diabetic dams. The 5 days old-diabetic rats presented increased SOD, GSH-Px and thiol in washed erythrocytes, and increased MDA concentration in the liver, while at term pregnant animals showed higher MDA concentration, and decreased SOD and catalase activities. The 15 days old offspring from diabetic dams presented higher insulin levels and antioxidant enzymes. These results suggest that glycemic alterations at different moments in the life of rats stimulate an antioxidant defense system in these rats and in their offspring in the first days of life