Cannabinoid 2 receptor agonist and L-arginine combination attenuates diabetic cardiomyopathy in rats via NF-ĸβ inhibition

Beta-caryophyllene (BCP), a cannabinoid 2 (CB2) receptor agonist has recently been found to have cardioprotective activity as an anti-inflammatory and antioxidant molecule. L-arginine (LA), a nitric oxide (NO) donor, is a potential regulator of cardiovascular function. Considering the role of CB2 receptor activation and NO regulation in cardiovascular diseases, the combination of BCP with LA may be a possible treatment of diabetic cardiomyopathy (DCM). Hence, we investigated the efficacy of the novel combination of BCP with LA on cardiovascular inflammation and oxidative stress in diabetic rats. DCM was induced by streptozotocin (55 mg/kg) in Sprague-Dawley rats intraperitoneally. BCP, LA, and BCP with LA were administered to diabetic rats for 4 weeks. After completion of the study, hemodynamic parameters, biochemical parameters, and inflammatory cytokine levels were analyzed. Also, oxidative stress parameters, nuclear factor kappa beta (NF-ĸβ) expression, and histopathology in cardiac tissues were estimated. The combination of BCP (200 mg/kg) with LA (200 mg/kg) significantly normalized the hemodynamic parameters and decreased the glucose, cardiac markers, interleukin-6, and tumor necrosis factor-alpha levels. Treatment of BCP and LA showed a significant decrease in oxidative stress and downregulated the cardiac expression of NF-ĸβ. Thus, the combination of BCP with LA improves cardiac functions by attenuating inflammation through NF-ĸβ inhibition in DCM.

The protective effect of Satureja bachtiarica hydroalcoholic extract on streptozotocin-induced diabetes through modulating glucose transporter 2 and 4 expression and inhibiting oxidative stress

CONTEXT

Oxidative stress plays an important role in development of diabetes mellitus. Satureja bachtiarica Bunge (Lamiaceae) is a rich source of bioactive compounds with antioxidant properties.

OBJECTIVE

This study investigates the antidiabetic effect of hydroalcoholic extract of aerial parts of S. bachtiarica.

METHODS AND MATERIALS

Male Wistar rats were randomly divided into six groups (n = 8) including control (normal saline), diabetic [Streptozotocin (STZ)], intervention (STZ plus hydroalcoholic extract of S. bachtiarica at doses of 75, 150 and 250 mg/kg/d) and positive control (STZ plus captopril 50 mg/kg/d) groups. A single intraperitoneal (IP) injection of STZ (60 mg/kg) was used to induce diabetes and IP therapy with drugs was performed for four weeks.

RESULTS

In diabetic rats, serum total antioxidant capacity (TAC) decreased significantly, but glucose, alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), γ-glutamyltransferase (GGT) and malondialdehyde (MDA) increased significantly as compared to the control (p < 0.05). Treatment with extract (250 mg/kg) caused a significant decline in serum glucose, GGT, ALT, AST and MDA as well as a significant increase in serum TAC (p < 0.05). During the intervention period, diabetic rats showed significant weight loss, but extract (250 mg/kg) treated rats did not show any weight loss. Extract (250 mg/kg) up-regulated GLUT2 expression and down-regulated GLUT4 expression in the liver (p < 0.05). S. bachtiarica extract at all dosage levels prevented STZ-induced histological damage of liver, kidney and pancreas.

DISCUSSION AND CONCLUSIONS

S. bachtiarica extract exhibits antidiabetic effects through modulation of oxidative stress and expression of GLUT2 and GLUT4.

The acute effects of different spironolactone doses on cardiac function in streptozotocin-induced diabetic rats

Currently, cardiovascular diseases are the leading cause of global mortality, while diabetes mellitus remains an important cause of cardiovascular morbidity. A recent study showed that patients with diabetes mellitus treated with mineralocorticoid receptor antagonists have improved coronary microvascular function, leading to improved diastolic dysfunction. In this study, we evaluated the influence of acute administration of spironolactone on myocardial function in rats with streptozotocin-induced diabetes mellitus, with special emphasis on cardiodynamic parameters in diabetic rat hearts. The present study was carried out on 40 adult male Wistar albino rats (8 weeks old). Rats were randomly divided into 4 groups (10 animals per group): healthy rats treated with 0.1 μmol/L of spironolactone, diabetic rats treated with 0.1 μmol/L of spironolactone, healthy rats treated with 3 μmol/L of spironolactone, and diabetic rats treated with 3 μmol/L of spironolactone. Different, dose-dependent, acute responses of spironolactone treatment on isolated, working diabetic and healthy rat heart were observed in our study. In healthy rats, better systolic function was achieved with higher spironolactone dose, while in diabetic rats, similar effects of low and high spironolactone dose were observed.

Effects of S-Allylcysteine on Biomarkers of the Polyol Pathway in Rats with Type 2 Diabetes

OBJECTIVES

We evaluated the effects of S-allylcysteine (SAC) on biomarkers of the polyol pathway in streptozotocin-nicotinamide (STZ-NA)-induced diabetes in rats.

METHODS

Diabetes was induced in male albino Wistar rats by intraperitoneal administration of STZ (55 mg kg^-1 bw^-1) and NA (110 mg kg^-1 bw^-1). SAC (150 mg kg^-1 bw^-1) was orally administered to the rats with diabetes for 45 days to assess its effects on blood glucose, insulin, insulin resistance, glycated hemoglobin, aldose reductase (AR), sorbitol dehydrogenase (SDH), sorbitol, fructose, thiobarbituric acid-reactive substances (TBARS), hydroperoxide, hemoglobin and glutathione (GSH).

RESULTS

On SAC administration in the rats with diabetes, the levels of blood glucose, insulin resistance, glycated hemoglobin, AR, SDH, sorbitol, fructose, TBARS and hydroperoxide increased significantly (p<0.05), whereas those of insulin, hemoglobin and GSH decreased. SAC showed therapeutic effects similar to those of gliclazide in decreasing blood glucose, AR, SDH, sorbitol, fructose, glycosylated hemoglobin, TBARS and hydroperoxides levels and significant increases in insulin, hemoglobin and GSH activity in rats with diabetes. Moreover, histopathologic studies also revealed the protective effect of SAC on pancreatic beta cells.

CONCLUSIONS

The results indicate that SAC prevents complications of diabetes by reducing the influx of glucose in the polyol pathway, thereby elevating the GSH level and reducing the activities of AR and SDH. Therefore, SAC may have imperative implications for the deterrence and early treatment of type 2 diabetes.

Chrysin treatment improves diabetes and its complications in liver, brain, and pancreas in streptozotocin-induced diabetic rats

Chrysin (CH) is a natural flavonoid with pharmacological influences. The purpose of the current study was the assessment of possible protective effects of CH against oxidative damage in the serum, liver, brain, and pancreas of streptozotocin (STZ)- induced diabetic rats. In the present study, the rats were divided into the following groups of 8 animals each: control, untreated diabetic, 3 CH (20, 40, 80 mg/kg/day)-treated diabetic groups. To find out the modulations of cellular antioxidant defense systems, malondialdehyde (MDA) level and antioxidant enzymes including glutathione-S-transferase (GST), superoxide dismutase (SOD), and catalase (CAT) activities were determined in the serum, liver, brain, and pancreas. STZ caused an elevation of glucose, MDA, TG, TC, LDL-C and with reduction of HDL-C, total protein, SOD, CAT, and GST in the serum, liver, brain, and pancreas (p < 0.01). The findings showed that the significant elevation in the glucose, MDA, TG, TC, LDL-C and reduction of HDL-C, total protein, SOD, CAT, and GST were ameliorated in the CH-treated diabetic groups versus to the untreated groups, in a dose dependent manner (p < 0.05). The current study offers that CH may be recovered diabetes and its complications by modification of oxidative stress.

Investigation of Propolis' Effect on Thiobarbituric Acid Reactive Substances and Anti-Oxidant Enzyme Levels of Hippocampus in Diabetic Rats Induced by Streptozotocin

BACKGROUND

Propolis is an organic resinous viscous substance collected from flower bud and plant sprig by bees. Propolis has a potential treatment agent for oxidative damage caused by diabetes in hippocampus due to its flavonoid and phenolic content.

AIM

In this study effect of propolis on thiobarbituric acid reactive substances and anti-oxidative enzyme levels of hippocampus in diabetic rats induced by streptozotocin was investigated.

MATERIALS AND METHODS

The study involved measuring levels of SOD, CAT, GSH-Px and TBARs in hippocampus tissue of STZ-induced diabetic rats (Adult Male Sprague Dawley rats) after applying propolis for one month. The subjects of the study were composed of 51 rats randomly assigned to four groups (Control, STZ, P+STZ and STZ+P). For analysis of data, Kruskal Wallis Test was utilized.

RESULTS

The findings of the study showed that there were no significant difference in the levels of TBARS, SOD, CAT and GSH-Px of hippocampus across the groups.

CONCLUSION

Propolis application in four-week duration does not have effect on TBARS, SOD, CAT and GSH-Px levels of hippocampus of diabetic rats. These findings mean that more time for observing oxidative harms on hippocampus is needed.