Chimonanthus nitens Oliv. leaves flavonoids alleviate hyperuricemia by regulating uric acid metabolism and intestinal homeostasis in mice

This study aimed to evaluate the alleviating effect of Chimonanthus nitens Oliv.leaves flavonoids(CLF)on hyperuricemia induced by potassium oxonate in mice.The results showed that CLF lowered the serum levels of uric acid(UA),creatinine and blood urea nitrogen,downregulated hepatic mRNA expressions of xanthine oxidase(XO),phosphate ribose pyrophosphate synthetase(PRPS)and adenosine deaminase(ADA)in hyperuricemia mice.In addition,CLF repaired renal injury by significantly down-regulating mRNA and protein expressions of renal UA reabsorption-related proteins and up-regulating the mRNA and protein expressions of UA secretory-related proteins.Finally,CLF inhibited UA synthesis and promoted UA excretion to alleviate hyperuricemia.Besides,CLF supplementation repaired the intestinal barrier function as demonstrated by significant increased mRNA levels of intestinal zonula occludens-1(ZO-1),Occludin,mucin 2(MUC2)and mucin 4(MUC4),as well as decreased mRNA levels of toll-like receptor 4(TLR4)and myeloid differentiation factor 88(MyD88)in mice.Further research showed that CLF treatment restored intestinal homeostasis mediated by improving the composition of gut microbiota and elevating the abundance of beneficial bacteria like Lactobacillus,Alistipes,Prevotellaceae_UCG-001 and Parasutterella.Overall,our findings revealed a novel function of CLF as a promising therapeutic candidate for the treatment of hyperuricemia.

Niacin alters the ruminal microbial composition of cattle under high-concentrate condition

To understand the effects of niacin on the ruminal microbial ecology of cattle under high-concentrate diet condition, Illumina MiSeq sequencing technology was used. Three cattle with rumen cannula were used in a 3 x 3 Latin-square design trial. Three diets were fed to these cattle during 3 periods for 3 days, respectively: high-forage diet(HF; forage-to-concentrate ratio = 80:20), high-concentrate diet(HC;forage-to-concentrate ratio=20:80), and HC supplemented with 800 mg/kg niacin(HCN). Ruminal pH was measured before feeding and every 2 h after initiating feeding. Ruminal fluid was sampled at the end of each period for microbial DNA extraction. Overall, our findings revealed that subacute ruminal acidosis(SARA) was induced and the a-diversity of ruminal bacterial community decreased in the cattle of HC group. Adding niacin in HC could relieve the symptoms of SARA in the cattle but the ruminal pH value and the Shannon index of ruminal bacterial community of HCN group were still lower than those of HF group. Whatever the diet was, the ruminal bacterial community of cattle was dominated by Bacteroidetes,Firmicutes and Proteobacteria. High-concentrate diet significantly increased the abundance of Prevotella,and decreased the abundance of Paraprevotella, Sporobacter, Ruminococcus and Treponema than HF.Compared with HC, HCN had a trend to decrease the percentage of Prevotella, and to increase the abundance of Succiniclasticum, Acetivibrio and Treponema. Increasing concentrate ratio could decrease ruminal pH value, and change the ruminal microbial composition. Adding niacin in HC could increase the ruminal pH value, alter the ruminal microbial composition.