Postnatal protein-undernutrition impacts on mental development and cognition in children and can lead to problem with attention and unresponsiveness which compromise children's ability to learn. These behavioral disorders might be due to alteration in calcium homeostasis as calcium plays critical roles in fundamental functions of neuron. The role of low protein diet as well as Se and Zn supplementation on intracellular calcium concentration ([Ca(2+)]i), Ca(2+)-ATPase, Na(+)-K(+)-ATPase, calpain and caspase-3 activities from rat cortex and cerebellum were investigated. Well-fed (WF) and low protein diet-fed (LPDF) rats were given diets containing 16% and 5% casein, respectively, for a period of 10 weeks. Then, the rats were supplemented with Se and Zn at a concentration of 0.15 mgL(-1) and 227 mgL(-1), respectively, in drinking water for 3 weeks. The results obtained from the study showed a significant increase in [Ca(2+)]i; calpain and caspase-3 activities as well as increase transfer latency in water maze study and reductions in Ca(2+)-ATPase and Na(+)-K(+)-ATPase activities for LPDF rats compared to WF rats. Se and Zn supplementation to LPDF rats reversed the elevation in [Ca(2+)]i, calpain and caspase-3 activities and restored the cognitive deficits and the activities of Ca(2+)-ATPase and Na(+)-K(+)-ATPase. Conclusively, protein-undernutrition results in the accumulation of synaptosomal calcium and inhibition of calcium transporters presumably via free radical generations and results in cognitive impairment which also probably results from neuronal death in rats through calpain activation and the caspase cascade mechanisms. However, Se and Zn supplementations ameliorated the anomalies observed.
The effect of ad libitum ingestion of selenium (Se) in drinking water (0.15 mg SeO2/L) for 3 wk on the brain weight, total brain protein, glutathione (GSH) level, catalase activity, and lipid peroxidation in the brain of protein-undernourished (PU) rats was investigated, in an attempt to determine whether antioxidants alone can reverse some of the neuropathological changes associated with protein undernutrition in rats. Feeding on a normal diet (16% casein) by well-fed rats or a low-protein diet (5% casein) by PU rats and Se-treated PU rats lasted 14 wk. Se-treated PU rats were given Se in drinking water during the last 3 wk of the experiment. Results show that protein undernutrition induced significant reductions (p < 0.001) in brain weight, total brain protein, and catalase activity (p < 0.05) while it induced a significant increase (p < 0.05) in lipid peroxidation when compared with well-nourished rats; but no significant effect was observed for the GSH level. However, the ingestion of Se in drinking water by PU rats for 3 wk resulted in significant increases (p < 0.05) in brain weight, catalase activity, and total brain protein but induced a significant reduction (p < 0.05) in lipid peroxidation when compared with PU rats given water. The values obtained for Se-treated PU rats are comparable with those obtained for well-nourished rats. The GSH level was, however, not affected by Se ingestion. We suggest that Se, by inducing increases in the concentration of certain proteins, including catalase, in the brain, abolished some of the pathological changes associated with protein undernutrition in the brain, and appears as a promising antioxidant in the prevention and management of pro-oxidant-induced brain damage.
Chemical modification of cellulose is currently attracting attention as researchers attempt to take advantage of the abundance of hydroxyl groups on its surface to introduce extra biological functionality. However, the possible deleterious effect of exposure to functionalized nanocellulose (CSN) remains a concern. Therefore, this study aims to explore the potential mechanisms of hepatotoxicity of CSN modified with oxalate ester (NCD) in rats. A 7-day repeated oral toxicity study of NCD at the doses of 50 and 100 mg kg−1 body weight was conducted, and plasma and liver tissue samples were assayed using biochemical analysis, liver histopathology, and protein expression. NCD, at both doses, did not significantly ( p > 0.05) alter the relative weight of liver, alkaline phosphatase activity, and lipid peroxidation levels of the animals. However, NCD at the dose of 100 mg kg−1 body weight significantly elevated aspartate aminotransferase, alanine aminotransferase, and myeloperoxidase activities. NCD also enhanced the immunohistochemical expression of inducible nitric oxide synthase and Bcl-2-associated X protein in the liver of rats. Histological observations revealed necrosis and severe cellular infiltration at the high-dose treatment. Our study provides an experimental basis for the safe application of NCDs.
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