TH蛋白和枸橼酸对尿草酸钙结晶动力学的影响的研究

Research of effects of tamm-horsfall protein and citrate on calcium oxalate crystallization kinetics

目的研究枸酸盐和TH蛋白对草酸钙的成核、积聚的影响。方法通过分光光度计在620μm时的OD值的测定可在过饱和溶液中观察草酸钙晶体的成核和积聚。观察参数包括诱导时间(inducetime),简写为TI,即形成可观察微粒所需的时间;成核曲线(slopeofnucleation)的速率,简写为SN,即分光光度计OD620所观察的曲线上升支;聚积曲线(slopeofaggregation)的速率,简写为SA,即下降支,以及加入枸酸酸,NTHP(正常人尿液中所提取的TH蛋白),SF-THP(结石患者尿液中所提取的TH蛋白)后对参数的影响。然后相互比较。结果在实验浓度分别为1.50、2.50和3.50mmol/L时,枸酸酸可增加TI和抑制晶体成核(78%￣87%),聚集(63%￣70%),P<0.001。NTHP在30￣40mg/L时,可抑制晶体成核,也可抑制晶体的聚集(76%￣81%)。在实验浓度下,ST-THP降低TI(P=0.001和标准情况相比)并且促进聚集(33%￣48%)。当和NTHP并存时,柠檬酸可增强NTHP的抑制作用。当和ST-THP并存时,柠檬酸可逆转ST-THP的促成核和促聚集作用。结论在NTHP和ST-THP存在的情况下,柠檬酸决定草酸钙晶体的成核和聚集。

[Objective] To measure the effects of THP on calcium oxalate (CaOx) nucleation and aggregation in presence or absence of citrate. [Methods] Nucl eation and aggregation of CaOx crystals from a supersaturated, stirred solution were studied by spectrophotometric time-course measurements of OD at 620 nm (OD6 20). Measured parameters were induction time tI (time to induce formation of det ectable particles), SN, (slope of increase of OD620, mainly due to crystal nucle ation), and SA, (slope of decrease of OD620 after equilibrium has been reached, due to crystal aggregation). Effects of citrate, NTHP and SF-THP on these parame ters were measured, [Results] At 1.50, 2.50 and 3.50 mmol/L, citrate increase d tI and inhibited crystal nucleation (by 78%~87%) as well as aggregation (by 63 %~70%), (P <0.001). Normal THP at 30 and 40 mg/L inhibited crystal nucleation a nd, more strongly, aggregation (inhibition 76%~81%). At all concentrations test ed, SF-THP reduced tI (P =0.001 vs standard conditions) and promoted aggregation (inhibition -48% to -33%). When simultaneously present with NTHP, citrate enhan ced the inhibitory effects of NTHP as well as turned promotory SF-THP into a cry stallization inhibitor. [Conclusion] Citrate appears to be the main determinan t of CaOx crystallization rates in the presence of nTHP as well as SF-THP.