| Objective: To study the pathophysiological mechanisms which microglial cells injured brain after intracerebral hemorrhage as well as the protection mechanism of minocycline, thus further discuss the injure mechanism of intracerebral hemorrhage and observe microglial cells changes after minocycline was used that will provide a theoretical basis for the clinical treatment of intracerebral hemorrhage. Methods: 1. Autologous blood was injected into the caudate nucleus of rat that produced intracerebral hemorrhage model. 2. 90 SD rats were randomly divided into 3 groups which were sham operation group, ICH group and treatment group. There were 30 rats in each group. Each group was observed at 6h, 24h, 2d, 3d, 5d and 7d after the model was produced. There were five animals at each time point. 3. Intervention methods: The treatment group rats were injected minocycline(45mg/kg) into the abdominal cavity at 6h and 24h after ICH onset. From then on once a day until the animals were put to death. The ICH animals received an equivalent amount of sterile saline at the same time point. In addition to surgical procedures, the sham operation group didn't inject autologous blood, and the other conditions were fully consistent with the ICH group. 4. The models were evaluated at 2h post the operation. Neurological dysfunction score was assessed at 6h, 24h, 2d, 3d, 5d, 7d post the operation. 5. Observed water content of brain tissue around the hematoma at different time points by wet-dry-weight method. 6. Measured TNF-αand IL-1βcontent around the brain hematoma at different time point by radioimmunoassay. 7. Apoptotic cells and microglial cells around the hematoma in each group were observed at the corresponding time points by immunohistochemistry and image analysis techniques. 8. Observed the leukocytes by HE staining. Results: 1. The sham operation group didn't take place obvious neurological dysfunction at each time point. The ICH group and the treatment group took place the most serious neurological dysfunction at 2d to 3d and the peak of treatment group was lower. The ICH group and the treatment group took place more serious neurological dysfunction (P<0.05) at each time point than the sham operation group. The treatment group compared with the ICH group had no statistic significance obviously at the 6h time (P=0.70>0.05) and 24h (P=0.65>0.05), had statistic significance obviously at others time points (P<0.05). 2. The sham operation group didn't take place obvious cerebral edema since the water content of brain tissue around the brain hematoma were equal at each time point. The water content of brain tissue around brain hematoma of ICH group had statistic significance obviously (P<0.05) at 6h, 24h, 5d and 7d compared with 3d, the treatment group also. The ICH group had no statistic significance obviously (P=0.47>0.05 ) at 2d compared with 3d, the treatment group also (P=0.42>0.05). The ICH group and the treatment group compared with the sham operation group occurred cerebral edema (P<0.05) at each time points. The treatment group compared with the ICH group had no statistic significance obviously at 6h (P=0.81>0.05) and at 24h (P=0.22>0.05), had statistic significance obviously (P<0.05) at the others time points. 3. The TNF-αand IL-1βcontent around brain hematoma of sham operation group did not change significantly at at each time point. The TNF-αcontent around brain hematoma of ICH group had statistic significance obviously (P<0.05) at the others time pionts compared with 2d. IL-1βcontent had statistic significance obviously (P<0.05) at 6h, 24h, 5d, 7d compared with 2d,and had no statistic significance obviously(P=0.24>0.05) at 3d compared with 2d. TNF-αcontent around brain hematoma of treatment group had statistic significance obviously (P<0.05) at 6h, 3d, 5d, 7d compared with 2d,and had no statistic significance obviously(P=0.18>0.05) at 24h compared with 2d. IL-1βcontent had statistic significance obviously(P<0.05) at 6h, 24h, 5d, 7d compared with 2d,and had no statistic significance obviously(P=0.07>0.05) at 3d compared with 2d. TNF-αand IL-1βcontent around brain hematoma of ICH group had statistic significance obviously (P<0.05) at each time point compared with the sham operation group,the treatment group also. The TNF-α(P=0.57>0.05) and IL-1β(P=0.47>0.05) content around brain hematoma of treatment group compared with the ICH group had no statistic significance obviously at 6h, and had statistic significance obviously(P<0.05) at the others time points. 4. The apoptotic cell and microglial cell quantity around brian hematoma of shame operation group were very few at each time point. The apoptotic cell quantity of ICH group and treatment group had statistic significance obviously(P<0.05) at the others time points compared with 3d. The microglial cells quantity of ICH group and treatment group had statistic significance obviously(P<0.05) at the others time points compared with 2d. The apoptotic cell quantity of ICH group and treatment group were significantly higher at each time point than the sham group, the microglial cells also. The apoptotic cell quantity (P=0.71>0.05) and microglial cell quantity (P=0.22>0.05) around brian hematoma of treatment group compared with the ICH group had no statistic significance obviously at 6h, and had statistic significance obviously(P<0.05) at the others time points. 5. By HE staining the brains of sham operation group couldn't be seen great amount of leukocyte infiltration at each time point. However, the brains of ICH operation group could be seen and took place obvious cerebral edema, especially at 2d to 3d. The treatment group took place less cerebral edema and were seen less leukocyte infiltration than the ICH group. 6. Linear correlation .The microglial cell quantity around brian hematoma of treatment group was siginificantly positively correlated with the apoptotic cell quantity of treatment group(r=0.723, P<0.01), was siginificantly positively correlated with IL-1βcontent(r=0.924, P<0.01), was siginificantly positively correlated with TNF-αcontent(r=0.761, P<0.01), was siginificantly positively correlated with brain water content(r=0.724, P<0.01), and was siginificantly negatively correlated with neurological dysfunction score (r=-0.863, P<0.01). The microglial cell quantity around brian hematoma of ICH group was siginificantly positively correlated with the apoptotic cell quantity of ICH group (r=0.797, P<0.01), was siginificantly positively correlated with IL-1βcontent (r=0.908, P<0.01), was siginificantly positively correlated with TNF-αcontent (r=0.880, P<0.01), was siginificantly positively correlated with brain water content (r=0.787, P<0.01), and was siginificantly negatively correlated with neurological dysfunction score(r=-0.760, P<0.01). Conclusion: 1. The ICH model of rat was made by autologous blood that is simple and make easily, and the changes of pathophysiology of rat models are as almost same as the ICH of patients, thus the model can be used generally. 2. TNF-α, IL-1β, apoptotic cells, microglial cells and leukocytes around the brian hematoma markedly increased after ICH that showed they took part in the pathophysiological process of the secondary damage after ICH. 3. Microglial cells were activated after ICH, and the peak of microglial cell quantity appeared more earlier than apoptotic cell. Microglial cell quantity was siginificantly positively correlated with apoptotic cells quantity, TNF-αcontent, IL-1βcontent and brain water content, was siginificantly negatively correlated with neurological dysfunction score. 4. Minocycline can significantly reduce the activation of microglial cells, reduce apoptosis cell around the hematoma, reduce release of TNF-αand IL-1βand mitigate cerebral edema, thereby it can protect neurons.
|
PDF Full Text Request