Immunophenotypic and molecular study in different tissues during life of the diabetic rats and their offspring

Abstract

The great majority of the experimental models use agents beta - cytotoxic, as streptozotocin (STZ), capable to inhibit the insulin synthesis in the beta-pancreatic cell,inducing the diabetes. Studies accomplished at our laboratory have been carried out to understand the pathophysiological mechanisms involved the severe diabetes and pregnancy in female rats, using the STZ (40 mg/kg) in the adult life of the animal. Our previous results showed that female rats with severe diabetes presented glycemia above 300 mg/dL, increased rates in the embryonic loss after the implantation, increased incidence of fetal anomalies and alterations in the system of antioxidant defense. Besides, female rats with severe diabetes exhibited increased levels of DNA damages (increased genotoxicity) in the presence or not of pregnancy. It is also known, that 90% of the diabetic patients presented type 2 diabetes mellitus (DM 2), althought further research on this subject is need. In our research group we have been studied mild diabetes, in which these animals present blood glycemia levels between 120 e 300 mg/dL. For the induction of mild diabetes the animals were treated with STZ in the neonatal period, which altered the maternal glycemia in the beginning of the pregnancy and it caused alterations in the organism maternal and/or embryonic, affecting the implantation process and subsequently the placental and fetal development. Also, an increased was observed in the activities of antioxidant enzymes in erythrocytes and placenta, suggesting that the increase of those biomarkers scavenging the free radicals after hyperglycemic picos. The female rats with mild diabetes presented glucose intolerance but presented no glycemic alterations at the end of the pregnancy. In another model of mild diabetes induction (administration of STZ in the neonatal period and in the pregnancy) was verified that the diabetic female rats presented alteration in the weight of the litter and in the percentage of pre and post-implantation losses, but the hyperglycemia was not verified in the fetal period. Indeed, doubts remain regarding the factors involved in glucose oscillations in rats with neonatally-induced mild diabetes specially due to the regenerative capacity of the beta pancreatic cells. In this study, through different methodological approaches we intended to advance knowledge on the proliferation processes and death of the beta-pancreatic cells during different phases of the life of rat. It will be used: the) technique of qRT-PCR real time; b) technique of induction of the mild diabetes, c) Western blotting, d) immunohystochemistry, and) morphometry, f) espectrophotometry, g) ELISA microplates. This project will develop with the researchers of another department collaboration (Internal Medicine) and other institutions (University of Medicine of Marília_FAMEMA and USP_São Paulo). Besides, this project will establish an multidisciplinar interaction (Molecular Biology, Cellular Biology, Hystology, Biochemistry, Embryology, Physiology and Genetics). At the end of this work, we intended to acquire knowledge on the pathophysiological mechanisms involved in the proliferation and in the death of the beta-pancreatic cells related to the diabetes and their consequences (hypoxia and oxidative stress) for reducing the harmful repercussions caused by this syndrome, especially on the obstetric and perinatal issues . (AU)