Effect of thymoquinone on high fat diet and STZ-induced experimental type 2 diabetes: A mechanistic insight by in vivo and in silico studies

The aim was to investigate whether thymoquinone (TQ) attenuates hyperglycemia-induced insulin resistance in experimental type 2 diabetes. Type 2 diabetes mellitus (T2DM) was induced by injection of streptozotocin (STZ, 40 mg/kg) in high fat diet (HFD) rats. The levels of glucose, insulin, area under curve (AUC) of glucose, lipid profile parameters, homeostasis model assessment of insulin resistance (HOMA-IR), peroxisome proliferator-activated receptor-γ (PPARγ), and dipeptidyl peptidase peptidase-IV (DPP-IV) were evaluated in HFD + STZ-induced type 2 diabetic rats. TQ treatment significantly reduced elevated levels of glucose, AUC of glucose, insulin, and DPP-IV in diabetic-treated groups. In addition, TQ treatment significantly reduced high levels of triglycerides (TG) and cholesterols (total, low-density and very low-density lipoprotein) accompanied by significant augmentation in high-density lipoprotein (HDL) levels in diabetic-treated groups. However, TQ treatment significantly improved insulin sensitivity in diabetic-treated groups, which was confirmed by increased level of PPARγ and decreased level of HOMA-IR. Molecular docking of TQ exhibited substantial binding affinity with PPARγ and DPP-IV target proteins, which is supported by in vivo results.

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Effect of Nigella sativa, atorvastatin, or L-Carnitine on high fat diet-induced obesity in adult male Albino rats

Obesity is increasing rapidly across the globe. It is widely accepted that natural products with a long safety background may modulate obesity. The current work aimed to investigate the effect of Nigella sativa, atorvastatin, or L-Carnitine on high-fat diet-induced obesity in white male albino rats. A regular basal diet was fed to 7 rats, and a high-fat diet (HFD) was fed to 24 rats throughout the study for 12 weeks. The HFD group was split equally into four subgroups, each containing six rats. The first group fed on HFD with no medication, the second group received HFD+ Nigella sativa, the third group received HFD+ atorvastatin, and the fourth group received HFD+L-carnitine. At the beginning of the seventh week (the start of the treatment regimen), Nigella sativa, atorvastatin, or L-Carnitine were administered for six weeks. Glucose, body weight, serum atherogenic index (AI), ALT, and AST activities were analyzed. The pathological alterations in the hepatic tissues were examined microscopically and scored. The results revealed that the HFD diet significantly increased the final body weight, serum AI, and serum levels of liver enzymes. Treatment with L-carnitine or Nigella sativa significantly normalized the lipid profile and decreased the final body weight, serum AI, and Serum ALT. Histopathological examination of the liver of HFD received rats showed features of steatosis, which were mitigated by the administration of Nigella sativa or L-Carnitine, while atorvastatin had no significant effect on the improvement of hepatic lesions. Collectively, study findings showed that Nigella sativa or L-Carnitine has mitigated effects on metabolic and histopathological changes in the liver tissues of rats fed with HFD.

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