Expression Of MDR1 And P-gp170 On Peripheral Blood Mononuclear Cells Of Patients With PNS

Objective To investigate the expression of MDR1mRNA and P-gp170 on Peripheral Blood Mononuclear Cell(PBMC) of patients with PNS at different time point and the role of them on the steroid resistance in the patients with PNS and the possible mechanism involved.Method 30 children with PNS without any glucocorticoid treatment before admission were divided into two groups(SSNS group and SRNS group),and 10 healthy children serving as control.Reverse transcription-polymerase chain reaction(RT-PCR) and flowcytometry(FCM) were applied to detect the expression of MDR1mRNA and P-gp170 on PBMC at different time point(1.before prednisone treatment;2.four weeks of after prednisone treatment;3.two months after finishing prednisone treatment or not in remission but the dose of prednisone were not more than 0.5mg/kg.day),Relation between P-gp170 expression and some clinical information were also analyzed.Results 1.Both the control and PNS were detected the expression of MDR1mRNA and P-gp170.2.A positive correlation was found between MDR1mRNA expression and P-gp170 expression(r=0.853,P＜0.05).3.Before the usage of GC,the expression of MDR1mRNA and P-gp170 in SSNS patients were both significantly higher than the control(P＜0.05),and both of them increased obviously after 4 weeks GC treatment (P＜0.05),but both of them decreased 2 months after the end of GC usage,which had no significant difference in contrast with the expression before GC treatment(P＞0.05).4. Before the usage of GC,the expression of MDR1mRNA and P-gp170 in SRNS patients were both significantly higher than the control(P＜0.01),and both of them increased obviously after 4 weeks GC treatment(P＜0.05),but both of them decreased 2 months after the end of GC usage or in the condition that the dose of prednisone less than 0.5mg/kg.day in the patients not in remission,however,when compared with the expression before GC usage,the difference was still significant(P＜0.05).5.The expression of MDR1mRNA and P-gp170 in SRNS patients were both significantly higher than that in SSNS patients at each three time point(P＜0.05).6.There were positive correlation between P-gp170 expression before GC usage and the relapse times(r=0.399,P＜0.05).The P-gp170 expression before GC usage in SRNS patients had positive correlation with 24h urine totole protein(24hUTP) and kidney pathology score(r=0.576,0.529,P＜0.05).Conclusion 1.The expressions of MDR1mRNA and P-gp170 were detected both in PNS patients and healthy children.2.A positive correlation was found between MDR1mRNA expression and the P-gp170 expression in PNS patients.3.The high P-gp170 expression may contribute to the GC resistance in PNS patients,and it may be severed as one possible mark of GC resistance.4.GC itself may induce the increase of P-gp170 expression,which may be one possible reason of GC resistance in some PNS patients.5.Having positive correlation with kidney pathology score and relapse times, P-gp170 expression may be useful in assessing the prognosis of PNS patients.