ascorbic-acid and melamine

Due to its high nitrogen content, melamine was deliberately added to raw milk for increasing the apparent protein content. Previous studies showed that melamine-induced apoptosis and oxidative damage on PC12 cells and rats' hippocampus. Several evidences suggested that vitamin antioxidant reduced oxidative stress and improved organic function. Whether treatments with antioxidant vitamins C or E, otherwise combination of them can attenuate oxidative stress after melamine administration remains to be elucidated. In this study, the reversible effects of vitamin antioxidants was investigated on melamine-induced neurotoxicity in cultured PC12 cells, an in vitro model of neuronal cells. When comparing vitamin C and E, the combination of both statistically increased PC12 cells viability. The results further showed that vitamin complex has effectively reduced the formation of reaction oxygen species, decreased the level of malondialdehyde, and elevated the activities of antioxidative enzymes. Hoechst 33342 staining and flow cytometric analysis of apoptosis showed that vitamin combination treatment effectively prevented PC12 cells from this melamine-induced apoptosis. It revealed the apoptotic nuclear features of the melamine-induced cell death. Additionally, a combination treatment of vitamins effectively inhibited apoptosis via blocking the increased activation of caspase-3. In summary, the vitamin E and C combination treatment could rescue PC12 cells from the injury induced by melamine through the downregulation of oxidative stress and prevention of melamine-induced apoptosis.

Topics: Animals; Antioxidants; Apoptosis; Ascorbic Acid; Caspase 3; Catalase; Cell Survival; Enzyme Activation; Glutathione Peroxidase; Lipid Peroxidation; Oxidative Stress; PC12 Cells; Rats; Reactive Oxygen Species; Superoxide Dismutase; Triazines; Vitamin E

Albeit the pathogenesis of cognitive impairment after exposure to melamine has not been fully elucidated, factors such as oxidative stress is thought to play potential roles. In the present study, we investigated the effect of treatment with vitamin C (150mg/kg) and vitamin E (200mg/kg) on the impairment induced by melamine. Three-week-old male Wistar rats were submitted to oral gavage with 300mg/kg melamine in 1% carboxymethylcellulose (CMC) for 28 days (MEL-SAL group). After treatment with melamine, animals received administration of a combination of vitamin C and vitamin E once a day for 7 days (MEL-VIT group). Both control (CT-SAL) group and pair-fed (CT-VIT) group received the same dosage of CMC and vitamin complex, respectively. Melamine-treated rats presented a marked decrease in learning and memory in the Morris water maze (MWM) as well as a reduced efficiency to find the platform in the reversal learning task. The rats treated with vitamins E and C had part of the above effects rescued in MWM tests, with mitigating the melamine-induced deficit in the learning and memory but slightly improving the reversal learning ability. The vitamins C plus E regimen mitigated melamine-induced impairment of hippocampal synaptic plasticity. It showed that the modulation of oxidative stress with vitamins E and C reduced melamine-induced damage. The data suggested that there was a novel therapeutic strategy to the cognitive dysfunction observed in melamine-induced neuropathy.

Topics: Animals; Ascorbic Acid; Body Weight; Hippocampus; Male; Neuronal Plasticity; Rats; Rats, Wistar; Reversal Learning; Spatial Learning; Triazines; Vitamin E

Nitrogen doped graphene (NG) was prepared by thermally annealing graphite oxide and melamine mixture. After characterization by atomic force microscopy and X-ray photoelectron spectroscopy etc., the electrochemical sensor based on NG was constructed to simultaneously determine small biomolecules such as ascorbic acid (AA), dopamine (DA) and uric acid (UA). Due to its unique structure and properties originating from nitrogen doping, NG shows highly electrocatalytic activity towards the oxidation of AA, DA and UA. The electrochemical sensor shows a wide linear response for AA, DA and UA in the concentration range of 5.0×10(-6) to 1.3×10(-3)M, 5.0×10(-7) to 1.7×10(-4)M and 1.0×10(-7) to 2.0×10(-5)M with detection limit of 2.2×10(-6)M, 2.5×10(-7)M and 4.5×10(-8)M at S/N=3, respectively. These results demonstrate that NG is a promising candidate of advanced electrode material in electrochemical sensing and other electrocatalytic applications.

Topics: Ascorbic Acid; Biosensing Techniques; Dopamine; Electrochemical Techniques; Graphite; Nitrogen; Triazines; Uric Acid