ABSTRACT
Cardiovascular diseases are the most important complications of diabetes, representing the ultimate cause of death in more than half of all patients with the disease. Nitrate has been demonstrated to be an effective add-on therapy in patients with heart failure but no study has been yet addressed the effect of nitrate therapy on myocardial injury associated with diabetes. The aim of this study was therefore to assess the effect of nitrate therapy on myocardial injury in type 2 diabetic rats. Thirty-two adult male Wistar rats were divided into four groups [n=8]: Control, control+nitrate, diabetes, and diabetes+nitrate. Type 2 diabetes was induced by injection of nicotinamide [95 mg/kg] 15 min before injection of streptozotocin [65 mg/kg]. Nitrate in control+nitrate and diabetes+nitrate groups was added to the drinking water [100 mg/L for 2 months]. Serum nitrate+nitrite [NOx], CK-MB, and LDH were measured before and at the end of the study and heart malonyldialdehyde [MDA] was measured at the end of the study. Nitrate therapy in diabetic rats significantly increased serum NOx levels [29.2 +/- 5.6 vs. 42.8 +/- 9.8 micromol/L, P<0.05], decreased heart MDA levels [9.7 +/- 1.2 vs. 6.2 +/- 0.6 micromol/L, P<0.05], and decreased serum levels of both CK-MB [471.0 +/- 29.7 vs. 284.9 +/- 10.3 U/L, P<0.05] and LDH [791.6 +/- 21.9 vs. 497.8 +/- 13.1 U/L, P<0.05]. Nitrate therapy provided cardioprotection by increasing NO levels and decreasing oxidative stress in type 2 diabetic rats
ABSTRACT
Humans can rarely be used as experimental models in medical researches, because of ethical issues. Therefore, some animal models, which have physiological systems similar to humans, are commonly used. In this regard, rats and mice are the most favorable species in research models. The thyroid gland has a key role in human growth and development and is essential for normal functioning of the body systems and tissues. The aim of this study was to review rat and mouse models of hyperthyroidism. Related articles published between 1975-2014 on hyperthyroidism in rat and mice were searched in Pub Med. Hyperthyroidism can be induced in animals using different doses of thyroid hormons [T3 and T4] by oral administration, injection, or with the diet. In addition, transgenic mice could act as a model of hyperthyroidism for the design of specific model of hyperthyroidism, such as Graves' disease. Animal models of hyperthyroidism could be used for studying the disease, treatment and identification of the molecular mechanisms involved. Pharmacologic agents are mostly used for creating animals models of hyperthyroidism because of their easy availability and low cost, compared to genetic techniques that are costly and expensive