| BACKGROUND AND OBJECTIVE:Diabetes mellitus is independent risk angent of acute cerebral infarction.37%-42% of clinical patients with acute cerebral infarction have diabetes. Diabetes seriously affected prognosis of acute cerebral infarction. So it was very important to investigate the physiopathologic mechanisms and preventive and therapeutic steps of acute cerebral infarction with diabetes. Drainage pathway of lymph of cerebral substance had been confirmed, but its meanings in acute cerebral infarction with diabetes had not been explained. We made use of qualitative and quantitative study to explain changes of drainage pathway of lymph of cerebral substance in acute cerebral infarction with diabetes, and investigate the effect on cell damge of nerve and vascular angiogenesis of acute cerebral infarction with diabetes after blocking drainage pathway of cerebral lymph.METHODS:1. semiquantitative analysis of cerebral lymphatic drainageAcute cerebral infarction (ACI) models were established by blocking middle cerebral artery occlusion referring to thread method, Diabetes mellitus model were induced by a single injection of STZ via the tail vein. Adult Sprague-Dawley rats were randomly divided into normal group, sham, only injecting tracers group, ACI group and DM+ACI group (first DM model, then ACI model were established). Evans Blue-labeled albumin(EBA) solution was injected into the rat caudate-putamen(CPu) with microsyringe under stereotaxic apparatus'control. Frozen sections of rat samples about brain, cerebellum, olfactory bulb, submaxillary lymph nodes, lymphoglandulae cervicales, lymphoglandulae cervicales profundae and lumbar lymph nodes were obtained at different time. and then detected fluorescence density in ice slide tissue respectively by fluorescence microscope respectively.2. quantitive analysis of cerebral lymphatic drainage Cerebral lymphatic blockade model were made by occlusion of cervical lympgatic vessels and the removal of its lymphatic nodes. Adult Sprague-Dawley rats were randomly divided into sham a, sham b, normal and non-CLB group, normal and CLB group, ACI and non-CLB group, ACI and CLB group, DM+ACI and non-CLB group, DM+ACI and CLB group.125I-HSA were injected into the lateral cerebral ventricle, and then plasma were collected for measuring contents of 125I-HSA in plasma through radioimmunity method at different time, the measured results were input a matlab procedure software designed by engineer and output pharmacokinetic parameter value Kα(h-1),Cmax(μg/ml),tmax(h).3. Effect of blockage of cerebral lymphatic drainage pathway in cerebral infarction with diabetes mellitusAnimals were randomly divided into sham a group,sham b group,ACI group,DM+ACI group and DM+ACI+CLB group(first CLB model were established and after 24h ACI model be done in diabetes rats.).The expression of VEGF,CD31,Bcl-2 and Caspase-3 were detected at different time by immunohistochemical method. Concentration of [Ca2+]i were determined by Laser Scan Confocal Microscope.RESULTS:1. Semiquantitive analysis of cerebral lymphatic drainage displayed that significant fluorescence signal were detected in olfACIory bulb at 12h, then common carotid artery adventitial space and submaxillary lymph nodes at 24h, then gradually lymphoglandulae cervicales, lymphoglandulae cervicales profundae and lumbar lymph nodes at 48h-72h. fluorescence signal density was the highest in submaxillary lymph nodes and was the the lowest in lumbar lymph nodes before 72h, the highest in lymphoglandulae cervicales profundae at 72h, the lowest still in lumbar lymph nodes. Fluorescence signal was lower in exrtracerebral lymphtic nodes and olfactory bulb of ACI group rats than those of simple tracers being injected group rats. Tracers being detected were more later in DM+ACI group rats than in ACI group rats and only injecting tracers group rats.2. Quantitive analysis of cerebral lymphatic drainage displayed that Values of Kα(h-1),Cmax(μg/ml) decreased and tmax(h) delayed significantly when ACI group being compared to norml and non-CLB group and DM+ACI group to ACI and non-CLB group (P<0.01). Values of Kα(h-1),Cmax(μg/ml) decreased by 57%,59% and tmax(h) delayed 4-5hours when normal and CLB group being compared to normal and non-CLB (P<0.01). by 50%,57% and 5hours when ACI and CLB group to ACI and non-CLB group(P<0.01). by 47%,32% and 5hours when DM+ACI and CLB group to DM+ACI and non-CLB group(P<0.01)3. The expression of VEGF,Bcl-2 and Caspase-3 were not detected and the expression of CD31 were detected slightly in normal group,sham a group and sham b group. The expression of VEGF,CD31 and Bcl-2 were lower in DM+ACI+CLB group than ACI group and DM+ACI group significantly, however, the expression of Caspase-3 and concentration of [Ca2+]i were higher than ACI group and DM+ACI group significantly.CONCLUSION:1. Acute cerebral infarction with diabetes could result in the loss of function of drainage pathway of cerebral lymph. The increasing degree of handicap of cerebral lymphatic drainage was one of most important mechanism of brain damages diabetes aggravated in cerebral infarction.2. Cell damages of nerve of acute cerebral infarction with diabetes were aggravated by bloking drainage pathway of cerebral lymph and the expression of VEGF, vascular angiogenesis and the expression of Bcl-2 decreased, the expression of Caspase-3 increased. So we concluded that the protective action of drainage pathway of cerebral lymph on acute cerebral infarction with diabetes depended on the regulation of vascular angiogenesis and related angents... |
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