Effect Of Fucoidan On Renal Injury In Hyperuricemia Mice

ObjectiveHyperuricemia is a metabolic disease characterized by long-term high levels of uric acid in the blood,which seriously endangers human health.Fucoidan is a sulfated polysaccharide existing in marine organisms,which has been used to treat kidney damage caused by diabetes.Currently,research on the effects of fucoidan on hyperuricemia mainly focuses on reducing uric acid levels and promoting uric acid excretion.It is unclear whether fucoidan has an improvement effect on renal damage caused by hyperuricemia.To explore the ameliorative effect of fucoidan on renal damage in hyperuricemic mice,the hyperuricemic mice model was established.Method1.Experimental grouping and design: After adaptive feeding for one week,mice were randomly divided into 6 groups(10 mice/group).Hyperuricemia model mice in MO group,LH group,HF group and AL group were induced by intragastric administration of potassium oxazinate(250mg/kg),adenine(100mg/kg)and yeast(1g/kg)every day.The normal control group(NC)was given 0.5%(w/v)sodium carboxymethyl cellulose by gavage;The fucoidan group(FC)was given fucoidan(300mg/kg)by gavage;Low dose fucoidan group(LF)was given fucoidan(150mg/kg)by gavage;High dose fucoidan group(HF)was given fucoidan(300mg/kg)by gavage;Allopurinol group(AL)was given allopurinol(25mg/kg)by gavage.The NC group and FC group were given normal diet,and other groups were given high yeast diet.The experiment lasted for 10 weeks,during which the mice have free access to rodent chow and tap water ad libitum.The mice were intraperitoneally injected with 40mg/kg pentobarbital sodium,the eyeballs were removed,blood was taken from the eyeballs and centrifuged,and the serum was stored at 4℃.The kidneys of mice were stripped for pathological observation and determination of subsequent indexes.2.Hematoxylin eosin staining was used to observe the pathological section of kidney tissue,transmission electron microscopy was used to observe the ultrastructure of kidney tissue,and TUNEL staining was used to observe the apoptosis of kidney tissue.3.The blood urea nitrogen(BUN)levels of mice were detected by automatic biochemical analyzer.4.The levels of serum uric acid(UA),creatinine(CR)and renal interleukin-1 β(IL-1β),interleukin-6(IL-6),interleukin-18(IL-18),tumor necrosis factor α(TNF-α)were detected by enzyme-linked immunosorbent assay(ELISA).5.The protein expression levels of phosphorylated nuclear factor κB p65(p-NF-κB p65),NOD like receptor thermal protein domain associated protein 3(NLRP3),cleaved caspase-1,interleukin 1β(IL-1β),BCL2 associated X protein(BAX),B-cell lymphoma-2(BCL-2),cleaved caspase-3,urate transporter 1(URAT1),and facilitated glucose transporter 9 polypeptide(GLUT9)were detected by Western blot(WB).Results1.Compared with the NC group,the weight of the MO group mice was reduced by45.6%(P < 0.05).Compared with the MO group,the body weight of mice in the HF group increased by 30.7%(P < 0.05).Compared with the NC group,the kidney index of the MO group mice was increased by 29.6%(P < 0.05).Compared with the MO group,the kidney index of LF and HF groups decreased significantly by 13.9% and 15.5% respectively(P <0.05).Compared with NC group,the food intake of MO group mice was reduced by 58.6%(P < 0.05).2.Compared with NC group,the serum UA,CR and BUN levels of the MO group mice were increased by 204%,275% and 1023% respectively(P < 0.05).Compared with the MO group,the serum UA levels of LF and HF groups were reduced by 58.6% and70.7%,respectively(P < 0.05).Compared with the MO group,the serum CR levels of LF and HF groups were reduced by 30.2% and 38.7%,respectively(P < 0.05).Compared with the MO group,the serum BUN levels of LF and HF groups were reduced by 18.0% and25.3%,respectively(P < 0.05).3.No significant abnormalities were observed in the renal tissue structure of the NC and FC groups.In the MO group,the renal tubules showed dilated lumens and contained transparent tubules.The epithelial cells around renal tubules and renal tubules showed obvious edema,necrosis and saccule-like changes.Glomerular cluster atrophy and inflammatory infiltration could be observed under an optical microscope.The above pathological changes were improved after fucoidan intervention.TUNEL staining revealed a significant increase in the number of renal cell apoptosis in the MO group compared to the NC group.The number of renal cell apoptosis decreased significantly after fucoidan intervention.Under electron microscopy,no significant abnormalities were found in the renal cells of the NC group.MO group showed foot process fusion.After fucoidan intervention,renal cell morphology tended to be normal.4.ELISA results showed that compared with NC group,the levels of IL-1β,IL-6,IL-18 and TNF-α in kidney of MO group were increased(P < 0.05).The levels of IL-1β,IL-6,IL-18 and TNF-α in kidney were decreased after the intervention of fucoidan(P < 0.05).5.WB results showed that compared with NC group,kidney expression levels of pNF-κB p65,NLRP3,cleaved caspase-1 and IL-1β in MO group were increased(P < 0.05).Fucoidan could reduce the levels of renal p-NF-κB p65、NLRP3、cleaved caspase-1、IL-1β protein expression level after intervention.Compared with NC group,BAX and cleaved caspase-3 expression levels in MO group were increased,and BCL-2 expression level was decreased in kidney(P < 0.05).The activation of apoptosis signaling pathway could be inhibited by the intervention of fucoidan.Compared with NC group,the expression level of GLUT9 in kidney of MO group mice was increased(P < 0.05).After fucoidan intervention,the expression levels of URAT1 and GLUT9 in kidney were decreased(P <0.05).Conclusion1.Fucoidan could reduce serum uric acid level,and effectively improve kidney damage caused by hyperuricemia and reduce renal uric acid reabsorption.2.Fucoidan supplementation could improve renal damage in hyperuricemic mice by inhibiting inflammation and apoptosis,and its mechanism may be related to downregulation of NF-κB/NLRP3 and BCL-2/BAX/Caspase-3 signaling pathways.