Carnosine decreased oxidation and glycation products in serum and liver of high‐fat diet and low‐dose streptozotocin‐induced diabetic rats

Abstract

High-fat diet (HFD) and low-dose streptozotocin (STZ)-treated rats provide useful animal model for type II diabetes mellitus. Oxidative stress and advanced glycation end products (AGEs) play a role in the development of diabetic complications. Carnosine (CAR) has anti-oxidant and anti-glycating properties. We investigated the effects of CAR on oxidation and glycation products in HFD+STZ rats. Rats were fed with HFD (60% of total calories from fat) for 4 weeks, and then a single dose of STZ (40 mg/kg; i.p.) was applied. Rats with blood glucose levels above 200 mg/dl were fed with HFD until the end of the 12th week. CAR (250 mg/kg body weight; i.p.; five times a week) was administered to the rats for the last four weeks. CAR significantly decreased serum triglyceride (TG) (57.7%), cholesterol (35.6%) levels and hepatic marker enzyme activities of HFD+STZ rats. It significantly reduced serum reactive oxygen species (ROS) (23.7%), AGEs (13.4%) and advanced oxidized protein products (AOPP) (35.9%) and hepatic TG (59%), ROS (26%), malondialdehyde (MDA) (11.5%), protein carbonyl (PC) (19.2%) and AGE (20.2%) levels. Liver steatosis and hepatocyte ballooning were also significantly reduced. However, CAR treatment did not alter serum glucose and blood glycated haemoglobin and hepatic anti-oxidant enzyme activities/mRNA expressions in HFD+STZ rats. Our results indicate that CAR decreased accumulation of oxidation and glycation products, such as MDA, AGE, AOPP and PC in the serum and liver and ameliorated hepatic dysfunction in HFD+STZ rats. This effect may be related to its anti-oxidative, anti-glycating, and anti-lipogenic potential.

Effect of Rosmarinic Acid and Sinapic Acid on Oxidative Stress Parameters in the Cardiac Tissue and Serum of Type 2 Diabetic Female Rats

“…It should be noted that in our study neither AOPP (a marker for protein oxidative damage) nor NPSH (of which reduced glutathione (GSH), an endogenous nonenzymatic antioxidant, is the main representative) changed after induction of the type 2 diabetes. Numerous studies indicate that in the course of diabetes the GSH level in the serum/plasma decreases and the level of protein damage markers increases [21,22,32,57]. Lack of such alterations observed in our study may result from the fact that in females, even in the type 2 diabetes, estrogens play protective role against oxidative stress [69], and the estrogen level in rats in our study did not change significantly after induction of diabetes.…”

“…Therefore, it can be concluded, that the model reflecting the changes observed in the type 2 diabetes in humans in the most adequate manner is a model in which a high-fat diet is combined with a single injection of a low dose of streptozotocin [52,53]. It should be noted that the majority of studies describing the effect of tested substances on parameters affected by both the type 1 and type 2 diabetes is based on the experiments conducted on male laboratory animals [17,[19][20][21][22][23][24][25][32][33][34][35]37,38,50,51,[54][55][56][57][58][59][60][61][62]. Following the suggestion of The National Institutes of Health (NIH) to use female animals in the laboratory studies [63] and reports about sex-dependent metabolic differences [64,65], our experiment was conducted on female rats.…”

“…Similarly to other reports, we observed increased random blood glucose level as well as the levels of fasting serum glucose, serum fructosamine, total cholesterol, and triglycerides. Moreover, induction of the type 2 diabetes resulted in the HOMA-IR increase and QUICKI decrease [32,35,54,[56][57][58]66]. There were also changes in the oxidative stress-related parameters in the serum.…”

Wenxin Keli Regulates Mitochondrial Oxidative Stress and Homeostasis and Improves Atrial Remodeling in Diabetic Rats

“…72 hours after injection, fasting blood glucose levels (FBG) were measured, and rats in the STZ injection group with blood glucose levels > 11 mmol/L were considered diabetic models and would be used in future experiments. This model involves a combination of a diet high in fat to bring about hyperinsulinemia, insulin resistance, and/or glucose intolerance followed by treatment with the β-cell toxin STZ, which results in a severe reduction in functional β-cell mass [19][20][21]. WXKL was kindly supplied by Shandong Buchang Pharmaceutical Co., Ltd. (Heze, China).…”

Synergistic Antibacterial Activity and Wound Healing Properties of Selenium-Chitosan-Mupirocin Nanohybrid System: An in Vivo Study on Rat Diabetic Staphylococcus aureus Wound Infection Model

“…A total of 30 adult male Wistar rats weighing 225 ± 15 gr were fed with a high-fat diet containing 25% lipids (10% cholesterol). Two weeks later, the single low-dose of streptozotocin (STZ; Sigma) at a concentration of 40 mg/kg body weight was injected intraperitoneally to induce type 2 diabetes 32,33 . The rats' blood glucose levels were measured after 72 hour by blood glucose monitoring systems (Medisign, Korea).…”