| A number of copper contaminants are released into the food chain because ofenvironmental pollution. Copper could bio–accumulate in human body through the food chain,thus affecting our food safety and endangering human health. When the accumulation ofcopper reaches to a certain amount, it will trigger the oxidative stress reaction in human body,inducing hepatic pathological changes, brain damage and neurasthenia. Researches haveshown that some lactobacilli have copper-binding-capacity, and lactobacilli are famous forsome immune regulation effect properties such as oxidation resistance and elimination of freeradical. Moreover, lactobacilli are widely used in the food industry and"generally regarded assafe (GRAS)". Therefore, it is important to study the potential effects of lactobacilli againstcopper toxicity. The purpose of this study was to screen lactobacilli withcopper-binding-capacity and copper-tolerance-capacity. One strain of Lactobacillusplantarum was isolated based on its good binding capacity and tolerance capacity to copper.The protective effects were further evaluated in vivo experiment. Its application in practicalproduction was considered as well.The copper-binding-capacity and copper-tolerance-capacity of16lactobacilli strainswere investigated in vitro. L. plantarum CCFM8246was selected with the bestcopper-binding-capacity and strongest tolerance to copper, which had the maximum uptakecapacity of19.7mg/g and grew well in MRS containing different concentration of copper ion(50mg/L,150mg/L,500mg/L).In order to evaluate the protective effects of L. plantarum CCFM8246against coppertoxicity in vivo, a copper intoxication animal model was established by orally introducingcopper sulfate by gavage (100mg/Kg,150mg/Kg). In prevention groups, L. plantarumCCFM8246was administrated at2×1010colony-forming units. Feces were collected andphysiological indicators were recorded every week. Learning ability and memory capacity inmice were examined by water maze test. Copper levels in organs and feces were determined.Biochemical analysis was also carried out for both serum and tissue homogenate. The resultsshowed higher levels of copper in feces of mice with L. plantarum CCFM8246treatment thanthat of the copper-treated groups. The highest can reach more than6times, indicating thatL. plantarum CCFM8246could effectively decrease intestinal copper absorption. The strainalso showed the great ability in reducing copper concentration in organs, up to75.9%. Copperaccumulates mainly in the liver, which is the critical target for copper toxicity, and couldcause injury in the brain. In contrast to the model group, the lactobacillus treatment reducedthe content of MDA (malondialdehyde) greatly and increased the content of SOD (superoxidedismutase) and GSH-PX (glutathione peroxidase), thereby enhancing the antioxidative defence system of mice. At the same time, L. plantarum CCFM8246could inhibit theincrease in the serum levels of AST (aspartate aminotransferase) and ALT (alanineaminotransferase) induced by copper toxicity. Besides, Water maze experiment showed thatthe administration of L. plantarum CCFM8246could alleviate intelligence injury caused bycopper exposure, and could improve the abilities of studing and memorizing. In conclusion,the results of the study confirmed that L. plantarum CCFM8246could protect mice againstcopper toxicity and it could be considered as a new dietary therapeutic strategy againstcopper-induced injury.The results of the application of L. plantarum CCFM8246in the fermented soymilkshowed that the strain grew well in the fermentation period and the fermented soymilk hadhigh sensory quality. Therefore, L. plantarum CCFM8246had the potential and advantages inthe application of soymilk fermentation, and could be utilized in the development of newproducts and commercial sales. |
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