Curcumin improves the metabolic syndrome in high-fructose-diet-fed rats: role of TNF-α, NF-κB, and oxidative stress

This study aimed to investigate effects of curcumin on high fructose diet (HFD)-induced metabolic syndrome (MetS) in rats and the possible mechanisms involved. MetS was induced in male albino rats (n = 20), over 8 weeks, by 65% HFD. For 8-week experiment period, rats were assigned to 2 equal groups: curcumin-treated rats received curcumin (200 mg/kg, p.o, once daily) along with HFD, and untreated rats were fed with HFD only. We evaluated body mass (BM), systolic blood pressure (SBP), homeostasis model assessment of insulin resistance (HOMA-IR), and serum levels of glucose, insulin, leptin, total cholesterol (TC), triglycerides (TGs), uric acid, malondialdehyde (MDA; lipid peroxidation product), and tumor necrosis factor-α (TNF-α; inflammatory cytokine), and serum catalase (endogenous antioxidant) activity and immunohistochemical expression of nuclear factor κB (NF-κB; inflammation-related transcription factor) in hepatocytes. HFD produced increases in BM, SBP, HOMA-IR, and serum levels of glucose, insulin, leptin, TC, TGs, uric acid, MDA, and TNF-α, a decrease in catalase activity, and strong positive expression of NF-κB in hepatocytes. Curcumin, in presence of HFD, produced significant improvements in all glucose and fat metabolism parameters, and in oxidative stress and inflammation biomarkers. Curcumin may potentially be useful in the treatment of MetS through its ability to modulate oxidation stress status and inflammation cascades.

Combination of Sitagliptin and Insulin against Type 2 Diabetes Mellitus with Neuropathy in Rats: Neuroprotection and Role of Oxidative and Inflammation Stress

AIMS

The present study evaluated the effects of sitagliptin-insulin against type 2 diabetes mellitus with neuropathy in rats and possible neuroprotective mechanisms.

METHODS

Diabetes was induced in 32 adult male albino rats by 6-week high-fat high-sugar diet followed by streptozotocin 30 mg/kg intraperitoneal injection. For 4 weeks thereafter, diabetic rats were divided into 4 groups, each group receiving one of the following daily: vehicle (untreated diabetic), insulin 10 IU/kg SC, sitagliptin 30 mg/kg PO or sitagliptin-insulin. We assessed systolic blood pressure (SBP), blood glucose, serum insulin and advanced glycation end-products (AGEs), thermal hyperalgesia and sciatic nerve tumor necrosis factor-alpha (TNF-α), superoxide dismutase (SOD) and malondialdehyde (MDA) and sciatic histopathology.

RESULTS

Compared to untreated and insulin-treated groups, sitagliptin decreased SBP, serum AGEs and sciatic MDA and TNF-α, and increased serum insulin and sciatic SOD, but insulin decreased blood glucose more. Sitagliptin-insulin (greater than sitagliptin or insulin alone) superiorly decreased and increased the above respective parameters, and ameliorated hyperalgesia and sciatic histopathological changes, but was similar to insulin in decreasing blood glucose, and similar to sitagliptin in rising serum insulin.

CONCLUSIONS

Sitagliptin-insulin combination produced hypoglycemic and neuroprotective effect and ameliorated hyperalgesia, oxidative stress and inflammation more than either drug alone. This combination might have clinical efficacy in uncontrolled type 2 diabetes with neuropathy.

Protective effects of combined β-caryophyllene and silymarin against ketoprofen-induced hepatotoxicity in rats

Ketoprofen (Ket), widely utilized in treatment of many inflammatory disorders, is found to induce liver toxicity especially with overdose. This study aimed to evaluate the possible protective effects of concomitant β-caryophyllene (Cary) and silymarin (Sily) against Ket-induced hepatotoxicity in rats. Forty adult male albino rats were divided into 5 groups (each n = 8): the control group received distilled water for 6 weeks; the Ket-treated group received distilled water for 5 weeks and Ket in a dose of 8 mg·kg−1·day−1 p.o. for the 6th week; the Cary + Ket treated group received Cary in a dose of 200 mg·kg−1·day−1 orally for 6 weeks and Ket for the 6th week; the Sily + Ket treated group received Sily in the dose of 150 mg·kg−1·day−1 for 6 weeks and Ket for the 6th week; and the Cary + Sily + Ket treated group received Sily and Cary for 6 weeks and Ket for the 6th week. At end of the experiment, serum ALT, AST, and albumin and liver total antioxidant capacity (t.TAC) and malondialdehyde (t.MDA) were measured in all rats. Ket increased serum ALT and AST and t.MDA and decreased t.TAC. Cary and Sily improved these changes. Combined Cary and Sily restored these liver changes to nearly normal. Combined Cary and Sily is hepatoprotective, with the ability to scavenge oxidants against Ket-induced hepatotoxicity in rats.

Role of the antidiabetic drugs: Glibenclamide and metformin on the contractility of isolated rat uteri

The current investigation has designed to study the role of two antidiabetics, glibenclamide and metformin on the spontaneous uterine contractions in the non-diabetic non-pregnant female rats. The rat uteri were isolated and allocated to two groups: 1)the glibenclamide group: After recording the normal spontaneous uterine contractions, the vehicle (ethanol) and glibenclamide molar concentrations (10(-7), 10(-6) and 10(-5) M) were analyzed on uterine contractions by recording on smoked paper on a rotating kymograph drum, and 2) the metformin group: After recording the normal spontaneous uterine contractions, the metformin concentrations (10(-7), 10(-6) and 10(-5) M) were analyzed on uterine contractions. Responses to the two drugs and vehicle control (ethanol) were recorded for 30 min. Glibenclamide has not significantly effected on the amplitude and frequency of spontaneous contractions of the isolated rat uteri. Metformin also has no significant effect on the amplitude and frequency of spontaneous contractions of the isolated rat uteri. In conclusion, the two oral antidiabetics glibenclamide and metformin have not changed both the amplitude and frequency of spontaneous uterine contractions in the non-pregnant non-diabetic female rats.