Intraventricular Administration Of Urokinase As A Novel Therapeutic Approach For Communicating Hydrocephalus

BackgroundCommunicating hydrocephalus is a usual neurological condition,which secondary to intracranial infection and hemorrhage diseases.The cause of hydrocephalus is consider to impaired flow or drainage of cerebrospinal fluid(CSF).Pathological dilation of cerebral ventricles is the character of this disease.Up to now,CSF shunting is the only definite therapy for communicating hydrocephalus.But shunting is not an ideal treatment for hydrocephalus,because of the related complications,such as obstruction and infection,causing high revision rates and high frequency of residual neurological deficits.Therefore,it is urgent for us to develop effective therapies for communicating hydrocephalus.Previous studies have reported that extensive fibrosis in the subarachnoid space,which is characterized by superfluous production of extracellular matrix(ECM),is implicated in different forms of communicating hydrocephalus,including post-hemorrhagic hydrocephalus.Hence,it may be a good therapeutic approach for communicating hydrocephalus to targeting at the fibrosis of subarachnoid space.Urokinase-type plasminogen activator(u PA),which is known as a serine protease,can convert plasminogen to plasmin.Plasmin is an active protease,it can degrade fibrin and ECM components.It was reported that activating the u PA/plasmin system could relieve lung fibrosis,airway fibrosis and liver fibrosis in relevant experimental models.Also intraventricular fibrinolysis was proven to improve the outcome after intraventricular hemorrhage.u PA,for some reason,is not available in the United States since 1999.In recent years,u PA received more and more concern for fibrinolytic therapy gradually.u PA-mediated fibrinolysis not only accelerated hematoma solution but improved outcome significantly in animal models of intraventricular hemorrhage,subarachnoid hemorrhage and intracerebral hemorrhage.However,at present,the effect of u PA on communicating hydrocephalus was unknown.Therefore,we use kaolin-induced communicating hydrocephalus of rats to test the hypothesis,that intraventricular infusion of u PA could alleviate communicating hydrocephalus by limiting fibrosis of subarachnoid space,thereby preventing the pathology of brain that induced by hydrocephalus and improving long-term neurocognition outcome.Part ? The establishment and assessment of rats model of communicating hydrocephalus.ObjectiveTo establish and assess rats model of communicating hydrocephalus.To observe the subarachnoid fibrosis of hydrocephalic rats.MethodsSprague–Dawley(S-D)rats were randomly assigned to two groups: sham group and kaolin group.Kaolin group were injected of 30 ?l of 25% kaolin suspension,which was dissolved in 0.9% sterile saline as 250 mg/m L,into the basal cistern.Sham group was injected of equal amount of 0.9% sterile saline.Animals received magnetic resonance imaging(MRI)examination at day 28 after operation,then all were euthanized for immunofluorescence and Western blot(WB).Results1.MRI scan showed that,compared with the sham group,ventricular volumes were enlarged distinctly in the kaolin group(P < 0.05).2.Immunofluorescence demonstrated that,in the subarachnoid space(SAS)of the kaolin group,a dense network of fibronectin and laminin was deposited,but there was little in the sham group.3.Similarly,WB analyses demonstrated that,compared with the sham group the expression of fibronectin and laminin were increased in the kaolin group(P < 0.05).ConclusionInjection of kaolin suspension into the basal cistern can successfully induse communicating hydrocephalus model in rats.Subarachnoid fibrosis,which is characterized by excessive extracellular matrix(ECM)production,is an important pathogenesis of communicating hrdrocephalus,and target it is expected to be the new direction for hydrocephalus treatment.Part ? Effect of u PA on communicating hydrocephalus in rats and its related mechanism.ObjectiveTo investigate whether u PA alleviates the development of kaolin-induced communicating hydrocephalus via reducing the fibrosis in the SAS.MethodsSprague–Dawley(S-D)rats were randomly assigned to sham group(saline injection),kaolin group(kaolin injection only),kaolin + vehicle group(kaolin injection with intraventricular injection of 0.9% sterile saline),kaolin + u PA group(and kaolin injection with intraventricular injection of u PA).MRI examination was performed on some rats(n = 6 per group)at day 3,14,28 after kaolin injection,then all these rats were euthanized at day 28 for immunofluorescence.The remaining rats(n = 6 per group)re ceived Morris water maze test from 23 to 28 after kaolin injection,then all rats were euthanized at day 28 for Western blot analysis.Fibronectin,laminin and glial fibrillary acidic protein(GFAP)expression were examined by immunofluorescence and WB.Results1.MRI demonstrated u PA administration significantly alleviated the enlargement of ventricular after kaolin injection(P < 0.05).2.Immunofluorescence and WB showed a much denser network of fibronectin and laminin was deposited in the subarachnoid space of kaolin group and kaolin + vehicle group compared with sham group(P < 0.05).While in the kaolin + u PA group,much less staining of fibronectin and laminin was seen in the subarachniod space compared with kaolin + vehicle group(P < 0.05).3.Likewise,Immunofluorescence and WB indicated that the expression of GFAP was increased in the kaolin group compared with the sham group(P < 0.05).And u PA treatment significantly reduced its expression in the kaolin + u PA group compared with the kaolin + vehicle group(P < 0.05).4.The neurocognitive function of kaolin group were worse than sham group(P < 0.05).And u PA improved neurocognitive function after kaolin-induced hydrocephalus(P < 0.05).ConclusionuPA may alleviate kaolin-induced communicating hydrocephalus by preventing the fibrosis of subarachnoid space.