Preparation Of Torularhodin And Its Effect On Chronic Kidney Disease Induced By High Fat Diet In Mice

Recent epidemiological studies have shown that high-fat dietary intake is an important factor in the increased incidence of chronic kidney disease（CKD）.CKD is now a global public health problem and its treatment is expensive,placing a heavy burden on society and family finances.Therefore,it is important to look for health-related functional foods to reduce the severity of CKD.Red yeast erythropoietin is a carotenoid found in microorganisms and has strong antioxidant capacity and antibacterial and anti-inflammatory effects as a natural functional ingredient.The aim of this study was to investigate the extraction process of red yeast erythrins and to predict and validate its effect on high-fat diet-induced chronic kidney disease in mice based on the network pharmacology as follows:（1）A kinetic model of red yeast fermentation was established by fitting a classical mathematical model,and an extended experimental validation was performed.The Logistic model and Luedeking-Piret equation were used for non-linear fitting,respectively,to establish the kinetic model equations for the growth of the bacterium and the production of torularhodin.The R2 values of the two model equations were 0.9952 and 0.9771,respectively,which were well fitted and could better reflect the dynamic trends of the indicators during the fermentation of red yeast.15 L The fermenter scaling-up experiment verified that the concentration of red yeast erythrins obtained from fermentation was 16.54×10^-3 g/L.（2）The extraction process of red yeast wall breaking was optimized,and the effect of different types of enzymes on the wall breaking effect of red yeast was studied.The results showed that lysozyme>β-mannanase>alkaline protease>cellulase>β-glucanase had a better effect on the wall breaking of red yeast.The combination of enzymes（lysozyme,β-mannanase,alkaline protease,cellulase andβ-glucanase）was more effective in breaking the wall.The highest extraction rate of 81.09%±1.40%of total carotenoids was found by single-factor and response surface experiments at 10 g/L enzyme addition,50°C enzymatic digestion temperature and 6 h enzymatic digestion time.The best extraction rate of 87.00%±0.29%was achieved by the combination of high pressure homogenization and enzymatic digestion.After breaking the wall,the red yeast body showed irregular shape,the surface was wrinkled and not smooth,the cell wall lost its integrity,the electrical conductivity increased,the specific surface area increased and the pore volume increased.（3）Predicting the mechanism of torularhodin intervention in chronic kidney disease based on network pharmacology.According to gene ontology and Kyoto Encyclopedia of Genes and Genomes analysis,the biological functions and key signaling pathways of torularhodinn intervention in chronic kidney disease are mainly related to biological functions such as inflammatory response and lipid response,mainly involving Toll Like Receptor（TLR）signaling,mitogen-activated protein kinase signaling and nuclear factorκB(N In addition,the potential of torularhodin to target TLR4 and other proteins in chronic kidney disease was verified by molecular docking technology.（4）Torularhodin intervene in chronic kidney disease caused by high-fat diet by regulating TLR4/NF-κB signaling pathway.Sporidiobolus pararoseus has antioxidant effects and significantly increased the levels of total superoxide dismutase,catalase and glutathione peroxidase in the kidneys of mice with chronic kidney disease,while inhibiting malon-dialdehyde accumulation.Torularhodin repairs,to some extent,the damage to kidney function and kidney structure caused by a high-fat diet.In addition,torularhodin significantly reduced the levels and m RNA expression of inflammatory factors such as tumour necrosis factorα,interleukin-6 and interleukin-1β,and activated the transcription and expression of TLR4,myeloid differentiation factor 88,β-interferon TIR domain bridging protein and NF-κB,key targets of TLR4/NF-κB signalling pathway,thus exerting anti-inflammatory effects.Moreover,the overall intervention effect of the small intestine targeted release group was superior to that of the rapid release emulsion group in both sets of complexes containing torularhodin.