| ObjectNow the interests on studies about the mechanism of brain damage following ischemia are focused on the inflammatory process after cerebral ischemia - reperfusion. Inflammatory cells participating in brain damage following infarction include endogenous (microglia) and extragenous ( polymorphonuclear leukocyte, neutrophil leukocyte, monocyte) cells. Both death and subdeath of neurons will cause mi-croglial cell activated and proliferating. Activated microglial cell and blood - derived monocyte will accelerate aeuron dissolved by releasing toxic substance, becoming phygocytic and immunoreactive, which promote brain damage following ischemia. Some studys indicate that TNF - a is mainly released by activated microglia after brain ischemi-a. TNF - a can initiate and regulate focal tissue inflammation. So TNF is a main cytokine controling brain - damage following ischemia.A large number of recent studies have confirmed that heparin, which has been extensively used to cure cerebral ischemia as typical anticoagulation drug, has strong effect in inhibiting inflammation. Its anti - inflammation and anticoagulation effects are achieved through different group of heparin molecular. But these studies are mainly on disease without ischemia or on cardiac muscle infarction. Studies a-bout whether it has effect on focal inflammation following cerebral ischemia are very few and there are no related reports in china. In this study, low molecular heparin is used after mice cerebral ischemia. The purpose is to examine if it has effect on microglial,monocyte acti-vation and TNF-a expression, to provide new pharmatical ground for heparin treatment and to provide theory grounds for developing new and - inflammation drug.Materials and methodsMale Wistar mice , weight 250-350, randomly divided, was used for brain ischemia - reperfusion model prepare. After 2 hours'oc-clusion the cerebral middle artery was reperfused. The animals of control and therapy group were killled after 3, 24, 48, 72 hours'survive (n=5). Sham operation and normal control group were also prepared ( n = 5). Open the thorax when mice were deeply anesthetized, Perfuse 0.9% natrii chloridi soonly via left ventricle. Remove the brain rapidly and keep it in the liquid nitrogen. 1. immunofluorescence. Frozen coronal brain sections (10m) were prepared for immuofluo-rescent method to label microglia and for HE dye. 2. Immunocyto-chemistry. Brain issues of 24h group were prepared for paraffine sections. The paraffine sections (4m) were used for TNF-a immuno-cytochemical dye and HE dye. 3. Statistic deal: Record the positive cells around infarction. The results were stated with t test. The difference is significant when P<0.05.Results1. The character of microglia and monocyte acvatition: There were a few activated microglias and monocytes in 3h group, ditributed as strip or strap. The activated cells manifold in 24,48h groups and located around infarction area. In contrast to 48h group , fewer posi-tive cells were found around infarction. But in the infarction , some positive cells can be found.2. The character of TNF - a expression cells' distribution: The positive cells mainly located around infarction area, uniformly to activated microglia and monocyte.3. The effect of heparin on microglia and monocyte activation; In contrast to control group , the number of positive cells in low - molecule - heparin therapy group decreased aparently in 24, 48, 72 hours group, (separately 46.6792±7.0719 vs 31.3833±5.4743(P<0. 001) ,57.3542±7.4090 vs 48.3208±8.4119( P<0.001) ,38. 8583±5.2119 vs 37.3458±3.7260(P=0.002)].4. The effect of heparin on TNF - a expression; Low - molecule - heparin can significantly inhibit TNF - a expression in 24h group. [35.5667±5. 8053 vs 22.9583±6.085(P<0.001)]DiscussionIn this study, low - molecule - heparin was used after mice brain ischemia in order to observe its effect on microglial, monocytic activation and TNF - a expression. The results showed heparin had apparently inhibited microg... |
PDF Full Text Request