The Effect Of Urokinase On Renal Injury Associated With Severe Acute Pancreatitis In Rats

IntroductionAcute pancreatitis ( AP) is a common and potentially fatal disease, and high mortality is characteristic of severe acute pancreatitis ( SAP). The mortality of SAP, with pancreas necrosis, is more than 14—35% .If inflammation necrosis reflects intensly, SAP may concurrent MODS , the mortality is highly to 40%. The pathogenic mechanism of AP has not been still completely illuminated. The traditional theory of abnormal enzyme activation and " the theory of oneself digestion" had not completely elucidated the pathogenesis of AP and its complicated course. Microcirculatory disorder, inflammation mediums, the release of cytokine and cyte - apoptosis are important factors. They are influenced and restricted each other. It is considered the most important factor of initiation, persistence and aggravation for microcirculatory disorder of pancrease and run through its entirely course of occurrence and development.SAP may combine with renal damage and even renal failure, cause pancreatic nephropathy. In the pathogenesis factors role of, the digestion enzyme of pancreas is activated and caused the abnormity of blood coagulation. Those come forth highly congeal state and cause severe microcirculatory disorder and conduce to be short of blood and oxygen in kidney. This cause the damage and failure of kidney. With extension of the course of disease in SAP, the blood flux of renal and perfusion descend, the increase of the ratio of TXB₂ and TXB₂/6 -keto - PGF1 α indicate the occurrence of the disorder of blood circulation in re-nal as it break the balance of TXA₂ and PGI₂.This study is on the basis of rats' SAP models to detect the treatment effect of urokinase on renal injury by observing the dynamic changes of renal blood flow ,TXA₂ and PGI₂, and renal tissue pathology changes.Materials and methods1. A total of 192 male Wistar rats ( provided by experimental center of the animal, weights ranged from 220g to 250g, were randomized into control group (C) ,pancreatitis group(P) and treatment group(T). Each group was divided into subgroup A and B. Rats in subgroup A were used to measure renal blood flow. Rats in subgroup B were drawn blood samples that were collected to observe the changes of TXA₂/PGI: levels and renal tissues pathologic changes. Each subgroup was divided into four small groups as the phases of 2h, 6h, 12h, 24h after SAP models was finished successfully, and control group was overturned duodenum only.2. Rats were fasted overnight before the: experiment but had free access to water. Following the Abo methods to establish SAP models, by using retrograde injection of 5% sodium taurocholate(5% NaTc, 0. 1ml/100g) into the cholan-giopancreatic duct, the injection rate was 0. lml per minute, and keep the injection pressure five minutes. And resumed the experiment after pancreas tissues showed edema and hyperemia. Duodenum was only flipped gently in the rats of group C. Urokinase (1000u/100g) was injected throught the inserted catheter into the left jugular vein 30 minutes after finishing the SAP model. Rats in subgroup B were drawn 4ml blood from inferior cava vein under anesthesia at the phase of 2h,6h,12h,24h accordingly after SAP model was finished triumphantly. Plasma was collected and stored at - 70℃, left renal were harvested from each rat and fixed in 10% buffered formalin.2. 1 Renal tissue blood flow ; Radioactive biomicrosphere technique was used to measure the renal blood flow at the phase of 2h,6h,12h and 24h.2.2 TXA₂/PGI₂ levels measurement; Measurement the levels of TXA₂/ PGI₂ with the methods of radioimmunoassay ( RIA)2. 3 Renal tissues were embedded in parsffin, cut sheets and HE tincture . With blind principle, one pathologyic who didnot pancipate experitments observed pathology changes by light microscope.3. Statistical management: SPSS 11. 5 statistical software was used.Results1. Renal blood flow: Comparing with group C, renal blood flow was decreased significantly ( P <0. 01) in all phases of group P and group T; Comparing with group P , renal blood flow in 2h,6h, and 12h phase of group T was significant increase ( P < 0. 01) , but the increase of blood flow in 24h phase of group T was not significant difference ( P > 0 05).2. TXA2 level; Comparing with group C, TXA2 levels were increased significantly ( P <0.01) in all phases of group P and group T, but comparing with group P, TXA2 levels were decreased significantly (P <0. 01) in all phases of group T.3. PGI2 level; Comparing with group C, PGI2 levels were decreased significantly (P <0. 01) in all phases of group P and group T, but comparing with group P, PGI2 levels were increased significantly ( P <0. 01) in all phases of group T.DiscussionThe pathogeneses of AP have been incompletely illuminated. Traditional theory of abnormal activation of trypsinogen and " the theory of oneself digestion" had not completely elucidated the pathogenesis of AP and its complicated course. The microcirculatory disorder, release of inflammation medium and the generation of cyte - apoptosis are important factors. They are influenced and restricted each other, but authentic relations have not been elucidated. It is considered the most important factor of initiation, persistence and aggravation for microcirculatory disorder of pancrease and run through its entirely course of occurrence and development.AP may cause renal injury. Its most change of morphology is the combine pathological changes of glomerulusNnephric tubule and kidney parenchyma, e-merge oedema and atrophy of glomerulus, glomerulonephritis and cellular necrosis of nephric tubule. The production in blood circulation that is released pare-nzyme activates kallikrein - kinin system possess the effect of nephrotoxicity, which induce vasoconstriction and osmolarity increase of glomcrulus. It appear secondary toxic effect of nephric tubule and kidney parenchyma. A numerous of data sheets show that, in many causative agent role of, pancreatic digestive zy-mogens, such as elastin proteolytic enzyme ..kininase lipase et. al, are activated. They have the role of nephrotoxicity to kidney, and destroy vessel wall of kidney, dilate blood vessel , increase vasopermeability and evoke bleed , throm and circulatory disorder. Pancreatin provoke to abnormality of hemagglutination, emerge hypercoagulabale state and evoke bloody urine.Lots of factors can lead to pancreatic circulation disorder, but TXA2 and PGI2 are the most important factors by the research of Shengdao,Z. TXA2 stimulates platelet aggregation and leads to the formations of microthrombi which are detrimental to the microcirculation. The effect of PGI2 is contrary to TXA2.Our experiment showed the levels of TXA2 in group P and group T significantly increased at all phases comparing with group C ( P <0.01) , the levels of PGI2 and pancreas blood flow in group P and group T significantly decreased at all phases comparing with group C ( P < 0. 01 ). This showed the balance of TXA2 and PGI2 disordered and pancreas blood irrigation decreased. The results were the same as the others reported previously.The main effect of urokinase is to activate fibrinolysin directly as a kind of fibrinokinase, lead to lysis of microthrombi, and improve the microcirculation. This study showed urokinase can improve the renal blood flow in SAP, especially at the phases of 2h,6h,12h (P <0.01) , the flow at phases of 24h increase but not significantly (P > 0.05).Urokinase has not direct effect on inflammatory mediator, the levels of TXA2 and PGI2 in group T changed significantly comparing with group P in this study, the probable reason was that urokinase could alleviate inflammatory response by improving pancreatic and systemic microcirculation, alleviating the in-...