The aim of this study was to assess the possible protective effects of Nigella sativa (NS) and its constituent, thymoquinone (TQ) on ethanol-induced gastric mucosal damage in an experimental model. Forty male rats aged four months were divided into four groups (each group containing ten animals); the control group received physiologic saline (10 ml kg(-1)) and the ethanol group had taken 1 ml (per rat) absolute alcohol by gavage. The third and fourth groups also received NS (500 mg kg(-1)) and TQ (10 mg kg(-1)) by gavage 1 h before alcohol administration, respectively. Both drugs (NS and TQ) could protect the gastric mucosa against the injurious effect of absolute alcohol and promote ulcer healing as evidenced from the ulcer index values. Gastric damage was confirmed histomorphometrically by significant increases in the number of mast cells (MC) and gastric erosions in ethanol treated rats. The NS treatment significantly decreased the number of MC and reduced the area of gastric erosions. Likewise, TQ treatment was also able to reduce the number of MC and the gravity of gastric mucosal lesions, but to lesser extent compared to NS. Gastric tissue histamine levels and myeloperoxidase activities were found to be increased in ethanol treated rats, and NS or TQ treatment reversed these increases. Results obtained from this study suggest that both drugs, particularly NS could partly protect gastric mucosa from acute alcohol-induced mucosal injury, and these gastroprotective effects could be due to their antiperoxidative, antioxidant and antihistaminic effects.

Diabetes mellitus is a common but serious metabolic disorder associated with many functional and structural complications. Glucose metabolism is disturbed due to an absolute or relative insulin deficiency. The experiment was carried out to determine the effect of melatonin on blood glucose and insulin concentrations, and histopathology of pancreatic beta-cells in streptozotocin (STZ)-induced diabetic rats. The rats were randomly allocated into one of the four experimental groups: group A (control), group B (diabetic untreated), group C (diabetic treated with melatonin for 6 weeks) and group D (diabetic treated with melatonin for 8 weeks); each group contained ten animals. Diabetes was induced in B, C and D groups by a single intraperitoneal (i.p.) injection of STZ (50 mg/kg, freshly dissolved in 5 mmol/l citrate buffer, pH 4.5). The rats in melatonin-treated groups were subjected to the daily i.p injection of 10 mg kg(-1) of melatonin for 6 or 8 weeks starting the day after STZ injection. Control and diabetic untreated rats were injected with the same volume of isotonic NaCl as the melatonin treated groups. Almost all insulin-positive beta-cells were degranulated, degenerated or necrotic in the STZ-treated rats leading to decrease in insulin secretion and an increase in blood glucose concentration. Melatonin treatment caused a sharp decrease in the elevated serum glucose, a slight increase in the lowered serum insulin concentrations and small partial regeneration/proliferation of beta-cells of islets. It is concluded that the hypoglycemic action of melatonin could be partly due to small amelioration in the beta-cells of pancreatic islets causing a slight increase in insulin secretion, it is mostly due to the extrapancreatic actions of the melatonin.

Aim: The protective effect of vitamin E (vit E) on cadmium (Cd) induced oxidative stress was studied in the blood of rats. Methods

The goal of this investigation was to study the protective effects of thymoquinone (TQ) and methotrexate (MTX) on collagen-induced arthritis (CIA) in rats. On day 0 under ether anesthesia, the experimental groups were immunized with 0.5 mg native chick collagen II (CII) solubilized in 0.1 M acetic acid and emulsified in Freund's incomplete adjuvant. Control rats were gavaged with vehicle, whereas CII was administered intradermally. In addition, arthritis treated with TQ group received TQ (10 mg kg(-1) bw by gavage once a week for 3 weeks starting on day 0); and arthritis treated with MTX group received MTX (MTX was suspended in corn oil and administered by gavage at 1 mg kg (-1) bw once a week for 3 weeks starting on day 0). A significant decrease in the incidence and severity of arthritis by clinical and radiographic assessments was found in recipients of therapy, compared with that of controls. The MTX treatment significantly (P<0.01) decreased the elevated serum NO, urea and creatinine in arthritic rats. Likewise, TQ treatment was also able to reduce significantly (P<0.05) serum NO, urea and creatinine levels, but to lesser extent than MTX. The histopathologic abnormalities are consistent with the hydropic epithelial cell degenerations and moderate tubular dilatation in the some proximal and distal tubules. The severity of the degenerative changes in most of the shrunken glomerules and vascular congestion were also observed in arthritic animals. Preventive treatment of TQ and especially MTX significantly inhibited kidney dysfunction and this histopathologic alterations. These studies indicate that TQ can be used similar to MTX as a safe and effective therapy for CIA and may be useful in the treatment of rheumatoid arthritis.

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