Kaempferol protects against streptozotocin-induced diabetic cardiomyopathy in rats by a hypoglycemic effect and upregulating SIRT1.

This study investigated if kaempferol could attenuate the oxidative, inflammatory, and fibrotic damage of the left ventricles (LVs) in streptozotocin (STZ)-diabetic rats by modulating silent mating type information regulation 2 homolog 1 (SIRT1) signaling. Adult male rats were divided into 5 groups (n = 12/each) as control, control + kaempferol, STZ-induced diabetes mellitus (STZ-DM), STZ-DM + kaempferol, and STZ-DM + kaempferol + EX-527, a sirtuin 1 (SIRT1) inhibitor. Administration of kaempferol to diabetic rats significantly preserved the systolic and diastolic functions of the LVs that was associated with a significant reduction in ventricular collagen deposition, infiltration of inflammatory cells, and protein expression of Bcl2-associated X protein (Bax), cleaved caspase-3, and cytochrome-C. In both the control and diabetic rats, kaempferol attenuated the loss in body weights, reduced fasting glucose levels, and increased fasting insulin levels and HOMA-ß. Besides, kaempferol lowered the levels of reactive oxygen species (ROS), malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6), downregulated the transforming growth factor-ß1 (TGF-ß1) and reduced the nuclear levels of NF-κB p65. In concomitant, kaempferol increased the LV levels of manganese superoxide dismutase (MnSOD) and glutathione (GSH) and stimulated the total protein levels of Bcl2, the nuclear activity of SIRT1, and nuclear levels of nuclear factor erythroid 2-related factor 2 (Nrf2). These events were associated with increased deacetylase activity and total levels of SIRT1 and a parallel decrease in the acetylation of Nrf2, NF-κB, smad2, and FOXO1. In conclusion: kaempferol attenuate diabetic cardiomyopathy in STZ-treated rats through its hypoglycaemic and insulin-releasing effects, as well as a cardiac independent mechanism that involves activation of SIRT1.

Hepatoprotective and Antioxidant Activity of Dunaliella salina in Paracetamol-induced Acute Toxicity in Rats.

Paracetamol has a reasonable safety profile when taken in therapeutic doses. However, it could induce hepatotoxicity and even more severe fatal acute hepatic damage when taken in an overdose. The green alga, Dunaliella salina was investigated for hepatoprotective and antioxidant activity against paracetamol-induced liver damage in rats. Male albino Wistar rats overdosed with paracetamol showed liver damage and oxidative stress as indicated by significantly (P<0.05) increased serum levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, total and direct bilirubin, malondialdehyde, cholesterol and nitric oxide. At the same time, there were decreased activities of serum superoxide dismutase and total antioxidant capacity compared with the control group. Treatment with D. salina methanol extract at doses of 500 and 1000 mg/kg body weight or silymarin could significantly (P<0.05) decrease the liver damage marker enzymes, total and direct bilirubin, malondialdehyde, cholesterol and nitric oxide levels and increase the activities of superoxide dismutase and total antioxidant capacity in serum when compared with paracetamol intoxicated group. Liver histopathology also showed that D. salina reduced the centrilobular necrosis, congestion and inflammatory cell infiltration evoked by paracetamol overdose. These results suggest that D. salina exhibits a potent hepatoprotective effect on paracetamol-induced liver damage in rats, which may be due to both the increase of antioxidant enzymes activity and inhibition of lipid peroxidation.