| Objective Fingolimod(FTY720)is synthesized from myriocin,which is isolated from the fungus Isaria sinclairii.It is rapidly phosphorylated by sphingosine kinase 2(SK2)in vivo to form FTY720-P,a sphingosine-1-phosphate(SIP)structural analogues,which acts at four G protein-coupled receptors S1P1,S1P3,S1P3,S1P4,and S1P5,thus regulating a variety of biological processes such as angiogenesis,cell differentiation and apoptosis,organ development,lymphocyte recirculation and bone metabolism.Angiotensin ?I(Ang?)is the main effector molecule inflammation in renin-angiotensin-aldosterone system(RAAS),which plays an important role in the development of chronic kidney disease(CKD).Ang?-induced renal damage exhibits glomerular mesangial cell proliferation,mesangial matrix deposition,tubular atrophy,dilation,cast formation,interstitial mononuclear cell infiltration and interstitial fibrosis.Previous studies have demonstrated the protective role of FTY720 in models of unilateral ureteral obstruction,subtotal nephrectomy,diabetes mellitus,anti-glomerular basement membrane glomerulonephritis.However,whether FTY720 exerts a protective role against Angll-induced renal damage characterized of mononuclear cells infiltration has not been reported.In the present study,we investigated whether FTY720 administration in rats submitted to Ang?-induced renal damage has protective role and explored its possible mechanisms.Methods 36 male Sprague-Dawley rats weighing 180-200g were randomly divided into 3 groups,12 rats of each:Ang? infusion group(subcutaneous continuous Angll infusion at 400ng/kg·min concentration),FTY720 intervention group(Ang?infusion at 400ng/kg·min concentration + FTY720 0.5mg/kg.d by means of intragastric administration)and normal saline group(the solution capacity was equal to Angll).24 hour urine was collected every week.Blood and kidneys were collected when rats were sacrificed at day 14 and 28 respectively.MDA and T-SOD assay Kits were used to detect the concentration of MDA and T-SOD in serum and kidney homogenates.Renal pathological changes was observed under light microscope.The expression and location of NADPH oxidase 4(Nox4)in renal was evaluated by immunohistochemistry,the expression of Nox4 in renal cortex was detected by Western Blot.Conditionally immortalized mouse podocytes was cultured and divided into control group,Ang?-stimulated group(at concentration of 0.1umol/L),FTY720 intervention group(5umol/L on the basis of Ang? stimulation)and FTY720-stimulated group(at concentration of 5umol/L),migration ability of each group was detected by wound healing assay.Results 1)Compared with the same peiord of normal saline group,the level of serum creatinine,urea nitrogen and urinary protein were significantly elevated in Ang? infusion group,while albumin was significantly decreased(P<0.05),these changes were time-dependent.FTY720-treated rats presented a decreased level of serum creatinine,urea nitrogen,urinary protein,and a significant increased content of albumin(P<0.05);2)Ang? infusion group showed a significant mesangial cells proliferation,mesangial matrix deposition,tubular epithelial cells effacement,a remarkable glomerular sclerosis and atrophy.While FTY720 alleviated these pathological changes effectively.3)The concentration of MDA in serum and kidney homogenates was significantly increased and T-SOD was significantly decreased(P<0.05)in Ang? infusion group as compared with control group;FTY720 partly reversed these changes significantly(P<0.05);4)Immunohistochemistry showed that Nox4 was mainly located in tubular,which expression was significantly upregulated in Ang? infusion group when compared with saline infusion group(P<0.05);FTY720 administration prevented the tendency of Nox4 expression significantly(P<0.05).The results of Western Blot were same to immunohistochemistry.5)Ang?-stimulated podocyte presented enhanced migration in vitro(P<0.05)as compared with control group,while FTY720 dramatically weakened podocyte migration(P<0.05).Conclusion FTY720 could attenuate renal pathological damage and ameliorated renal function by decreasing renal oxidative stress and protecting podocyte. |
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