Studies On Renal H～+-K～+-ATPase Activity Inhibited By Trimethyltin Chloride

Objects:to study on the renal H+-K+-ATPase(HKA)activity inhibited by Trimethyltin chloride (TMT)and to illuminate the mechanism of TMT induced hypokalemia.Methods:(1)The rat was executed by decapitation,and the kidney was got,preparing nephridial homogenate(10%).According to the method of enzymatic activity Kit,to assess the effection of renal HKA activity induced by different homogenate concentration,reaction time, ouabain and sch28080,to decide the best experiment condition.In the reaction system,adding various concentrations of TMT(0,5,25,125,625μM),measure the renal HKA activity,using HKA special inhibitor--sch28080 as QC.(2)24 SD rats were divided into 4 groups randomly and given TMT(ip)of 0,10,21.5 and 46.4 mg/kgbw,respectively;after 1 hour,collecting arterial blood from heart to run blood gas analysis;then executing rats by decapitation,getting plasma to measure K~+,Na~+,Cl~-,GLU,CK,CK-MB,LDH,HBDH,AST,ALT.One side of kidneys was used to measure renal HKA and Na+-K+-ATPase(NKA)activity,another to HKA immunofluorescence and histopathology.(3)36 SD rats were divided into 6 groups randomly.3 test groups were given TMT(ip)of 10mg/kgbw,3 control groups was given normal sodium(ip), After administration of TMT for 0,2,5 days,starting 24-hour metabolism test,collecting 24 h urine,to detect K~+,Na~+,Cl~-,GLU and CR,Following the methods above to treat animals.Using multiple linear regression to analyze the correlation relationship of blood K~+,pH,urine K~+,pH and renal HKA activity.(4)using SD rat's renal tube to culture the epithelium cells and using keratin immunofluorescence method to identify the cells and using immunofluorescence to observer the expression of renal HKA.Whole-cell patch clamp records to measure the role of TMT to renal CCD cells and using Laser Scanning Confocal Imaging System to measure the effection of TMT to intracellular pHi of CCD cells.Results:In this reaction system,increasing the TMT concentration,HKA activity in nephridial homogenate dropped from 18.33 to 13.07(μmolPi/mgpro/h)(P＜0.01),with the according of sch28080,and show dose response relation(R=0.790,P＜0.01).After administrations of TMT (10,21.5,46.4mg/kg),induced hypokalemia(P＜0.01)and blood pH decent(P＜0.05),and inhabited the renal HKA activity(P＜0.01).Linear correlation analysis showed the relationship of HKA activity with blood potassium levels(R=0.631,P＜0.05)and blood pH levels(R=0.778, P＜0.01)was positive correlation.After treated with TMT(10mg/kgbw)1,3,6 days,dropped blood potassium and blood pH,increased urine potassium discharge capacity and urine pH (P＜0.01)significantly and renal HKA activity inhabited evidently(P＜0.01).Linear correlation analysis shows the relationship of HKA activity with blood potassium(R=0.699,P＜0.01)and blood pH(R=0.540,P＜0.05)was positive correlation,but the relationship with urine pH(R= -0.843,P＜0.01)was negative correlation.The correlation relationship between HKA activity and urine potassium and urine discharge capacity isn't obviously.TMT caused the opening of K channels in cultured renal epithelial cells;TMT decrease of pH_i in cultured renal epithelial cells.Conclusion:That TMT inhabited the renal HKA activity,it caused the dysfunction of reabsorbing potassium ion and secreting hydrogen ion,induced potassium ion leakage from kidney and hydrogen ion storage in body.Clinical symptom is kaliopenia and acidosis.