The Effects Of Tacrolimus On The Expression Of MDR1 And P-gp170 In Renal Tissue Of Rats With Poor Hormone Efficacy Nephrotic Syndrome

Objective:Establishing rat model of nephrotic syndrome?NS?and detecting expression of multidrug resistance gene 1?MDR1?and protein P-glycoprotein 170?P-gp170?in the kidney of rats with poor hormone efficacy nephrotic syndrome after tacrolimus intervention,to investigate the possible mechanism of tacrolimus in the treatment of poor hormone efficacy nephrotic syndrome and its clinical significance.Methods:Healthy male SD rats?weight:180g-200g?were fed one week,then those with appropriate body weight and normal 24 hours urinary protein?n=100?were randomly divided into model group?n=80?and sham operation group?n=20?.The model rats were anaesthetized by intraperitoneally injected 10%chloral hydrate?3.0ml/kg?,then remove left kidney via dorsal longitudinal incision under sterile condition,5mg/kg and 2mg/kg of adriamycin?ADR,doxorubicin hydrochloride?were intravenously injected one week after surgery and three weeks after surgery respectively.In the sham operation group,0.9%saline was injected into the tail vein of the rats after being operated with the same procedure mentioned above except that the real removal of kidney was replaced by only dissceting to the renal capsule then sutureing.Fourth weeks after modeling,24 hours urine protein was detected and 72 NS rats model were established successfully.All SD rats were divided into five groups,group A:control group?sham operation group?,free access to feed and water,detection for 12 weeks;group B?NS model group?,free intake of feed and water,detection for 12 weeks;group C:prednisone treatment group?steroids sensitive group?:after intragastric administration of prednisone?10mg/kg.d?,those having curative effect were considered as hormone sensitive group,detection for 8 weeks;group D:Tacrolimus group,those without effective result after 4 weeks of prednisone treatment were given tacrolimus?0.5mg/kg.d?by gavage for 4 weeks;group E:?steroid resistant group?,those be fail in treatment with prednisone for 4 weeks were given the same dose of solvent as tacrolimus,detection for 8 weeks.Group A and group B were treated with the same dose of solvent by gavage.Blood sample were collected at the first day,the fourth week,the sixth week,the eighth week,and the 12^thweek.Urine were collected in the metabolic cage for 24 hours and 24 hours urine protein were detected.Some rats were sacrificed at the end of 8 weeks and the the remaining rats were killed at the end of the 12week,rat kidney were collected and sectioned,the renal pathologic changes were observed under light microscope with HE and Masson staining,podocyte changes were observed under electron microscope,MDR1 mRNA expression were detected by real-time fluorescence quantitative PCR and P-gp170 expression were detected by immunohistochemical method.Results:?1?The expression of MDR1 mRNA and P-gp170were observed in renal tissue in all group.?2?The expression of MDR1 mRNA and P-gp170 in renal tissue of group B,group C,group D and group E were significantly higher than those in group A at the end of the eighth week?P<0.05?.?3?The expression of MDR1 mRNA and P-gp170 in renal tissue of rats in group C was significantly higher than that in group B?P<0.01?.?4?The expression of MDR1 mRNA and P-gp170 in renal tissue in group D at the end of the 12 weeks were lower than those at the end of the eighth week?P<0.05?and the expression of MDR1 mRNA and P-gp170 in group D was lower than that of group C at the end of the 12^th week?P<0.01?,.?5?MDR1 mRNA expression were highly correlated with P-gp170 expression in the rat tissue.?r=0.93,P<0.05??6?In the Group E,the P-gp170 expression in renal proximal tubule was positively correlated with 24 hours urine protein?r=0.84,P<0.05?.?7?At the end of the 12^th week,pathological change including the fusion of foot process were all observed in the group B,C,D and group E.The pathological changes of E group were severer than those of group C.Conclusion1.The expression of MDR1 and P-gp170 in renal tissue of nephrotic syndrome rats was increased with poor hormone efficacy.2.The application of steroids may lead to the overexpression of MDR1 mRNA and P-gp170 in renal tissue of rats with poor hormone efficacy nephrotic syndrome.3.The high expression of P-gp170 in renal tissue of nephrotic syndrome rats may be one of the mechanisms of tacrolimus in the treatment of nephrotic syndrome with poor hormone efficacy.