The Effects Of Sporidiobolus Pararoseus Powder And Its Pigments On Diabetic Nephropathy Mice

In recent years,diabetic nephropathy has become one of the major health-impairing diseases as the percentage of sick people increases.For a long time,China has always amassed the world’s largest diabetics.However,the treatment methods for diabetic nephropathy are relatively scarce and mainly based on drug therapy.Therefore,it is of great significance to prevent the occurrence and improve the development of diabetic nephropathy through regulating diet and lifestyle.Sporodiobolus pararoseus JD-2 can ferment high quality carotenoids and other functional components,and its excellent antioxidant activity provide a new direction for prevention and treatment of diabetic nephropathy.The wall-breaking method of Sporodiobolus pararoseus JD-2 was firstly researched in this dissertation.Then a wall-breaking method with high breaking efficiency and carotenoid retention rate was selected and optimized.Followed with the obtention of yeast powder through freeze-drying,the nutrient composition of it was briefly analyzed.According to the improvement effect of yeast powder on diabetic nephropathy mice,it could be inferred that the carotenoids played a major role.Then the carotenoids were extracted and isolated from yeast powder to explore protective effect and its mechanism on diabetic nephropathy mice.The results of the study are as follows:(1)The best technology for the cell-wall breaking of Sporodiobolus pararoseus JD-2 was the high-pressure homogenization method.The optimized parameters are as following: the concentration of the yeast liquid is 8%,the homogenization pressure is 80 MPa,the continuous homogenization is 3 times,which lead to 78.3% wall-breaking rate and 82.5% carotenoid extraction rate.This wall-breaking technology is safe,simple and suitable for large-scale industrial production.(2)The analysis of the composition of the yeast powder was carried out.The results showed that the content of total carotenoids in yeast powder was 0.614 mg/g,and the main composition was torularhodin(0.053 mg/g),torulene(0.193 mg/g),γ-carotene(0.052 mg/g),β-carotene(0.316 mg/g).(3)To a certain extent,the yeast powder can mitigate the development of diabetic nephropathy in mice.Compared with mice in model group,yeast powder can effectively improve the "three more and one less" symptoms of diabetic mice,reduce the levels of BUN and CRE.A significant reduction was observed of 24-hour urine volume and proteinuria in yeast powder group.Yeast power intervention also increased the level of SOD and T-AOC and decreased the MDA content.What’s more,yeast power group of high dose showed a similar effect as positive control group(metformin hydrochloride),which indicated that the yeast powder significantly increased the antioxidant capacity in mice and reduced the oxidative stress damage caused by diabetic nephropathy.(4)Carotenoids in yeast powder was obtained through extraction and isolation,and then feed to mice with diabetic nephropathy by the route of intragastric administration.After the intervention with carotenoids,the body weight of mice was increased steadily,the daily feed intake and water intake was decreased,while the variation of fasting blood glucose were not significant.In addition,the level of BUN,CRE and proteinuria was decreased,and renal morphological lesions were improved.Furthermore,Nrf2 and NQO1 protein expression in the kidney was significantly enhanced,as well as the mRNA expression of gene related in Nrf2/ARE signaling pathway.The results indicated that carotenoids in Sporodiobolus pararoseus JD-2 enhance the antioxidant capacity of diabetic nephropathy mice by regulating the expression of genes related in Nrf2/ARE signaling pathway,to slow the damage of oxidative stress and delay the occurrence and development of diabetic nephropathy.In summary,the intracellular pigments and nutrients of Sporodiobolus pararoseus JD-2 can get better use after wall breaking by high pressure homogenization.The carotenoids obtained from Sporodiobolus pararoseus JD-2 have a favorable antioxidant activity and improvement effect on diabetic nephropathy.Moreover this effect is closely related to the increase of antioxidant enzyme activity mediated by Nrf2/ARE signaling pathway.This study provides new ideas for the prevention and treatment of diabetic nephropathy,as well as a theoretical basis for the development and application of Sporodiobolus pararoseus JD-2.