ABSTRACT
The generation of reactive oxygen species (ROS) plays an essential role in the pathogenesis of several diseases. Its implication in inflammation has suggested a possible link between oxidative stress and activation/release of cytokines in precancerous states. Recent observational studies have suggested an association between inflammation and vitamin D deficiency; hence, suggesting that vitamin D could play a role in the pathogenesis of diseases. This study examined the antioxidant and anti-inflammatory potentials of vitamin D in diethylnitrosamine (DEN)-induced oxidative stress and inflammation in rats. Rats were divided into four experimental groups. While groups one and two were administered twice weekly with 30 mg/kg body weight DEN for six weeks, groups three and four were given normal saline. Groups one and three were fed with vitamin D deficient diet, while groups two and four were fed vitamin D diet during the experiment. After that, biomarkers of oxidative stress status were assayed spectrophotometrically. The concentration of inflammatory cytokines was determined using enzyme-linked immunosorbent assay (ELISA). DEN-induced vitamin D deficient diet group had increased antioxidant enzymes' activities. Also, there were elevated concentrations of thiobarbituric acid reactive substances (TBARS) and inflammatory cytokines in the same group. Vitamin D diet, however, reduced oxidative stress effects through the reduction in the activities of TBARS and caused a significant (p < 0.05) increase in nitric oxide concentration. Vitamin D diet significantly (p < 0.05) reduced the level of interleukin 1ß and TNF-α produced in the deficiency state. These findings show that vitamin D may play an essential role in the regulation of hepatic oxidative stress and inflammatory responses.
ABSTRACT
In order to investigate the influence of some fibre-enriched diets on tissue lipids in an animal model of obesity induced by the administration of monosodium glutamate (MSG), obese rats were fed diets containing 30% of Acha, Cassava, Maize and Plantain for five weeks and weight gain, feed intake and lee index were recorded. The lipid profiles of plasma, erythrocytes, kidney, heart and liver as well as hepatic 3-hydroxyl-3-methylglutaryl-CoA (HMG-CoA) reductase activity were measured. The diets significantly (p<0.05) reduced weight gain and lee index in the obese rats. Obesity-induced increase in plasma and erythrocytes lipid levels was significantly (p<0.05) reduced by these diets. MSG-induced obesity also resulted in a significant increase (p<0.05) in hepatic cholesterol level which was reduced by the diets. MSG-obesity was characterised by a significant (p<0.05) increase in cholesterol, triacylglycerol and phospholipids in kidney and this was reversed by the diets except Maize which did not reverse the increased cholesterol level. Only Acha reversed the obesity-induced increase in heart cholesterol and phospholipids. The increased activity of hepatic HMG-CoA reductase associated with obesity was also significantly (p<0.05) reduced by the diets. In conclusion, dyslipidemia associated with MSG-induced obesity could be attenuated by consumption of fibre-enriched diets.
