Effects of OAT1/3 differential expression and competitive inhibition on renal tubular injury induced by aristolochic acid Ⅰ
Objective Utilizing probenecid(PRB)as an inhibitor of organic anion transporter(OAT)1 and 3,to investigate the acute injury of renal tubular epithelial cells in rats induced by aristolochic acid I(AAI)and elucidate the pathway through which AAI enters renal tubular epithelial cells.Methods Male Sprague-Dawley rats were randomly assigned to five groups:the blank control group,the solvent control(PEG300)group,the PRB(150 mg·kg-1)group,the AAI(80 mg·kg-1)group,and the AAI+PRB(80 mg·kg-1+150 mg·kg-1)group.Administer ig once every two days for four consecutive doses.Observed the renal organ index of rats,and biochemical analyzer detected serum creatinine(CREA)and urea nitrogen(UREA)levels.Hematoxylin-eosin(HE)staining was employed to examine the pathological alterations in renal tissue.Immunohistochemical(IHC)staining was conducted to assess the tissue localization and protein expression levels of OAT1 and OAT3 in renal tubules.Immunoelectron microscopy was utilized to investigate the subcellular localization and expression levels of OAT1 and OAT3 in renal tubular epithelial cells.Results Compared with the solvent control group,the renal index,CREA,and BUN levels in the AAI group were significantly increased(P＜0.01,0.001);Compared with the AAI group,the renal index,CREA,and BUN levels were significantly reduced in the AA I+PRB group(P＜0.05,0.001).HE staining revealed cellular edema,necrotic shedding,microvillous loss in proximal convoluted tubule epithelial cells(PCTEC)in the AAIgroup(P＜0.05).Conversely,in the AAI+PRB group,the incidence of vacuolar degeneration in PCTEC decreased significantly(P＜0.05)without other observed pathological changes.Additionally,a minor degree of vacuolar degeneration was observed in distal convoluted tubule epithelial cells(DCTEC)in both the AAIand AAI+PRB groups.IHC and electron microscopy revealed that OAT1 was predominantly expressed in the basolateral membrane of PCTEC,while OAT3 was primarily expressed in the basolateral membrane of DCTEC.Following exposure to AAI,the expression of OAT1 exhibited a decreasing trend in the proximal convoluted tubule(PCT)(P＜0.05),whereas the expression of OAT3 showed an increasing trend in the distal convoluted tubule(DCT)(P＜0.05).Conclusion AAI induces damage to both proximal convoluted tubules(PCT)and distal convoluted tubules(DCT),while PRB inhibiting OAT1 and OAT3 demonstrates improvement in renal function and reduction in pathological damage to renal tubular epithelial cells.These findings suggest that OAT1 may primarily facilitate the entry of AAI into PCTEC,whereas OAT3 may serve as the primary route for its entry into DCTEC.
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