Mechanism Of Urokinase In The Formation Of Kidney Stone

Objective:To observe calcium oxalate crystal growth and aggregation in vitro with the urokinase, to provide experimental evidence of inhibition of urokinase to calcium oxalate stones; to test the serum level of urokinase of organism and discuss the inhibition of the urokinase to kidney stone; to study the effect of urokinase in MDCK cells damage induced by oxalate, to discuss the inhibitive mechanism of urokinase in renal calculus. To prove the inhibition of urokinase to the formation of stone and provide a new therapeutic direction for kidney stone.Methods:Firstly, Based on calcium oxalate crystal growth and aggregation, distilled water (Blank group), different concentrations of citrate (control group) and urokinase (experimental group) were prepared and added into stone solution, size and aggregation of oxalate crystal of the solutions under inverted microscope were observed to prove inhibition of urokinase in vitro.27cases of patients with calculus (stone group) and24healthy people (control group) were divided into two groups, the serum level of urokinase of all subjects was measured by enzyme-linked immuno-sorbent assay(ELISA), biochemical detection method test serum calcium level and renal function (serum creatinine), analysis correlation of urokinase and calcium ion or creatinine. MDCK cells were cultured respectively. On the fifth day of primary culture, cultured cells were exposed to oxalate (5mM)for2hours with or without100.000units urokinase in the medium, Malonaldehyde(MDA) and lactic dehydrogenase(LDH)of the medium was determined; The activity of MDCK was also determined by CCK-8at0.5h,1h,1.5h,2h; The cell surface adhesion of crystals was observed under inverted microscope.Results:crystal volume in blank group is significantly bigger and easier to mutual aggregation than control group and experimental group, calcium oxalate crystal growth and aggregation in control group and experimental group are heavyly suppressed; Serum level of urokinase with stone group is lower than normal group (ug/L:0.49±0.15vs1.44±0.55,P<0.05), calcium level higher than those in control group (mmol/L:2.30±0.18vs2.18±0.13,P<0.05), serum creatinine concentration (umol/L:(54.38,126.26)vs(46.53,83.24),P<0.05),Stone group of urokinase level change with calcium and creatinine level were negatively correlated (r=-0.741/-0.459respectively,P<0.05). In cell experiments, MDA and LDH of oxalate and urokinase group were significantly higher than control group(P<0.05), compared with urokinase group, MDA and LDH of oxalate groups in cell culture medium are more higher (P＜0.05), as cell vitality declined, urokinase of cell vitality decreased significantly compared with the oxalate, calcium oxalate crystals adhesion to the cell surface of urokinase was significantly lighter than oxalate under Inverted microscope.Conclusions:Urokinase reduce damage to renal tubular epithelial cells, and restrain the growth and aggregation of calcium oxalate crystals. Kidney stone formation can be inhibited by urokinase.