The Effects of Gold Nanoparticles and Nanocrystalline Cellulose on Intestines and Biomarkers in Mice

Author:Li Juan Juan

Supervisor:zhou feng shan cha rui te


Degree Year:2019





Nanomaterials possess high surface area,strong adsorption ability,and good bioavailability,which could be used for treating bacterial infections and obesity.Gut microbiota could promote the formation of biological barrier,immunizaion,digestion,and alimentation.It is essential to maintain the balance of gut microbiota.Oral administration of antibiotics would destroy the gut microbiota,and even induce drug resistance.We used 4,6-diamino-2-mercaptopyrimidine(DAPT)modified gold nanoparticles(D-Au NPs)to treat infections induced by E.coli in gut,and studied the effect of D-Au NPs on gut microbiota,tissue,and biomarkers after a 28-day administration of Au NPs.D-Au NPs cure the infections in gut more effectively than antibiotic,and never disturbed the gut microbiota.After long-term administration,DAu NPs were harmless to intestinal epithelial cells and could significantly increase the relative abundance of typical probiotics and protect the gut microbiota without affecting the α-diversity.D-Au NPs showed no liver or kidney toxicity after 28 days.D-Au NPs which inhibited the imbalance of microflora could be used as alternatives to antibiotics for therapy of bacterial infections.Obesity threaten the world.Nanocrystalline cellulose possesses several advantages,such as wide source,simple preparation process,low cost,and high crystallinity.Nanocrystalline cellulose can not be digested by gastric acid or provide energy for body,so it would provide benefit for treatment of obesity.We studied the effect of nanocrystalline cellulose on mice which were fed with different foods such as normal diet and high fat diet.Nanocrystalline cellulose inhibited the increase of bodyweight of mice which were feeded by normal and high fat diet,and decreased the bodyweight of obese models effectively.It could reduce accumulation of lipid,and promote the transformation of white adipocyte to brown adipocyte.Nanocrystalline cellulose can reduce blood glucose and lipids in mice fed with different diets.Nanocrystalline cellulose promoted the consumption or transformation of low-density lipoprotein by reducing free triglycerides.Nanocrystalline cellulose could promote gene expression related to lipid metabolism in liver,increase lipid metabolism rate,inhibit the formation of fatty liver,and promote the formation of fatty liver to return to normal quickly.In conclusion,Nanocrystalline cellulose can maintain the weight of mice and lose weight quickly.Oral toxicity of nanocrystalline cellulose was studied by feeding nanocrystalline cellulose under different dietary conditions.Cytotoxicity experiments showed that nanocrystalline cellulose had no obvious toxicity to mouse intestinal epithelial cells,and the cell survival rate was higher than 90%.Oral administration of nanocrystalline cellulose can promote glucose metabolism in high fat diet mice and obesity model mice.Oral administration of nanocrystalline cellulose never affect the gastrointestinal morphology,livers,kidneys,and the level of inflammatory cytokies of mice fed with different diets.