Effects of Low Intensity Exercise Against Apoptosis and Oxidative Stress in Streptozotocin-induced Diabetic Rat Heart

Background The aim of this study was to investigate the effects of low intensity exercise on heart of streptozotocin (STZ)-induced diabetic rats. Materials and Methods The rats were randomly divided into 3 experimental groups: A (control), B (diabetic untreated), and C (diabetic treated with low intensity exercise); each group contains 8 animals. B and C groups received STZ. Diabetes was induced in 2 groups by a single intraperitoneal (i.p) injection of STZ (40 mg/kg, freshly dissolved in 0,1 M citrate buffer, pH 4.2). 2 days after STZ treatment, diabetes in 2 experimental groups was confirmed by measuring blood glucose levels. Rats with blood glucose levels of 250 mg/dl or higher were considered to be diabetic. Animals in the exercise group were made to run the treadmill once a day for 4 consecutive weeks. Exercise started 3 days prior to STZ administration. Results After induction of diabetes, histological abnormalities were observed, including myofibrillar loss, vacuolization of cytoplasm and irregularity of myofibrils. These alterations were attenuated by low intensity exercise. Our data indicates a significant reduction of oxidative stress and apoptosis in cardiomyocytes after exercise. Treatment of diabetic animals with low intensity exercise, decreased the elevated tissue malondialdehyde (MDA) levels and increased the reduced activities of the enzymatic antioxidants superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) in cardiac tissue. Conclusion These findings suggest that low intensity exercise has a therapeutic protective effect in diabetes by decreasing oxidative stress and apoptosis, and by preservation of myocardial integrity.

Effect of heparin, tissue plasminogen activator, and increased intracaval pressure on the acute morbidity of Greenfield filter insertion

The effects of anticoagulation, thrombolytic therapy, and augmented intracaval pressure on the risks of acute caval hemorrhage from Greenfield filter insertion have not been rigorously investigated. To examine these risk factors, the device was placed in three groups of five dogs. Group 1 served as controls, with filter placement only. Groups 2 and 3 received anticoagulants before surgery. Group 3 was additionally given a continuous infusion of tissue plasminogen activator begun immediately after filter insertion. Animals were killed after a 6-hour period of observation and measurement. A second phase was carried out at autopsy in group 3: intracaval pressure was augmented and its effects on caval integrity noted. During the period of observation there were no significant decrements in central venous pressure or hematocrit. At autopsy, no evidence of caval hemorrhage and no caval perforations were found. Increased intracaval pressure did not alter these findings. These results support the clinical experience with the device, and suggest that the risk of acute hemorrhage from a properly seated filter is minimal, even with concurrent use of heparin and thrombolytic agents or high caval pressures.