| Part 1 The manifestation of Magnetic resonance imaging of 3-day-old neonatal rats with different degrees of hypoxic ischemic brain damage.Objective(1)In this study, we established a model of hypoxic ischemic brain damage in 3-day-old neonatal SD rats to explore:(1)The imaging findings of conventional magnetic resonance imaging(MRI) and diffusion weighted imaging( DWI)performance in neonatal rats with different degrees of hypoxic ischemic brain damage.(2)The value of DWI in early diagnosis of hypoxic ischemic brain damage. Materials and methodsChoose 3-day-old neonatal SD rats a total of 104 which were healthy and clean grade,50 female rats, 54 male mice, weighing about 7.3-10.7g, average value: 8.9 ± 0.15 g, they were randomly divided into three groups: blank control group of 15, sham operation control group of 15, model group of 74.The left common carotid artery ligation of the model group were performed after anesthesia,and postoperative recovery for 1 hour,then the rats were placed in the oxygen concentration of 8% and the nitrogen concentration of 92% and the ambient temperature is 37℃ of the closed container,continuously hypoxia for 1h, 2h, 3h, made of different degrees of HIBD animal model, respectively for 1H hypoxia model group(n = 19), hypoxia model 2H group(20), hypoxia model 3H group(35).Take the same time born only exposure of unilateral carotid artery,which without ligation and hypoxia in newborn rats(n = 15) as the sham operated control group; another take the same time was born without any treatment of the newborn rats(n = 15) as the blank control group.The MRI and DWI scan were performed respectively in 6-12 h,12-24 h,3d,7d and we observed the general conditions of each of the rats in each time period after the successful of the model.Took the bilateral frontoparietal cortex and subcortical District, the bilateral hippocampus, lateral periventricular brain white matter, bilateral thalamus for the region of interest(ROI), and measured parts of the apparent diffusion coefficient(ADC) and analysis the differences of the same part of the ADC values within groups and between groups.Results(1)3-day-old neonatal SD rats were found to have different degrees of motor behavior abnormalities after the hypoxia ischemia model was successfully produced, Such as convulsions, restlessness, skin hair dark and dry, independent activities to reduce, can not stand up and other symptoms.while the normal control group and sham operated group showed no significant abnormal behavior.(2)Magnetic resonance imaging performance: Compared with the normal control group, the lesions of 1H model group were mainly distributed in the left and the left cortex and subcortical areas, the value of ADC decreased before 3d, and returned to normal at 7d;The lesion site of 2H model group was mainly distributed in the left and the lower part of the cortex and the left hippocampus, the ADC value was the lowest in 6-12 h, and then increased gradually, and returned to normal at 7d;The lesion of the 3H model group were mainly distributed in the left cortical and subcortical zone, the right side of the cortex and subcortical District, left hippocampus, left lateral ventricle and left thalamus, widely distributed, the left cortical and subcortical areas were damaged most seriously.The control group and sham operation group, conventional MRI and DWI showed no significant abnormal signal.Conclusion(1)The early lesions of HIBD mainly distributed in the cortex and subcortical zone;The longer the hypoxic time, the wider the range of diseases,the lower the lesions of the value of ADC.(2)DWI can be more early detection and prognosis evaluation of HIBD lesions and it was an important method to check the HIBD.Part 2 The Experimental Study of changes of S100 B protein expression and TTC staining in different degrees of HIBD in 3-day-old neonatal ratsObjective In this study,we established a model of hypoxic ischemic brain damage in 3-day-old neonatal SD rats,then detected the S100 B protein concentration in serum and TTC staining to explore:(1)The value of serum S100 B protein in the early diagnosis of hypoxic ischemic brain damage in neonatal SD rats.(2)The relationship between the level of serum S100 B protein and the severity of brain injury.(3) The concentration of serum S100 B protein appeared time,peak time and the disappearance of time after the neonatal SD rats with hypoxic ischemic brain damage, and provide early diagnosis and brain damage assessment for hypoxic-ischemic brain damage of neonatal clinical.(4)The results of TTC staining were matched with the diffusion weighted imaging and to further verified the extent of cerebral ischemia.Materials and methods(1)Choose 3-day-old neonatal SD rats a total of 136 which were healthy and clean grade,male and female,weighing about 7.5-11.8g, average value: 9.3±0.3g,randomly divided into 3 groups: blank control group of 8, sham operation group of 8 and HIBD model group of 120.According to the different time of hypoxia,the HIBD group were randomly divided into 3 groups, namely, the 1H hypoxia model group, the 2H hypoxia model group, the 3H hypoxia model group. Blank control group, sham operation group, each model group took blood at 0h, 12 h, 24 h, 3d, 7d respectively after successful model production and stayed fresh brain tissue for TTC.(2)Detection of S100 B protein expression in serum with ELISA method(double anti sandwich method). Then TTC staining was performed in fresh brain tissue.Result(1)Compared with the sham operation control group and blank control group,the serum levels of S100 B protein of HIBD group were increased at each time point, P < 0.05, the difference was statistically significant,and HIBD group at 24 h, the concentration value of S100 B protein reached the maximum value.The levels of serum S100 B protein in each time point of statistical analysis: Compared with the control group,the serum S100 B protein concentration did not change significantly, P > 0.05, the difference was not statistically significant;Compared with the sham operation group,the serum S100 B protein concentration did not change significantly, P > 0.05, the difference was not statistically significant;There was no significant difference between the control group and the sham operation group, P > 0.05, the difference was not statistically significant.The results showed that the S100 B protein concentration in the sham operated control group was stable, and was not affected by the operation factors.(2)The results of TTC staining showed that the area of the infarct area was almost identical to that of the abnormal signal area of the diffusion weighted imaging.Conclusion(1)S100B protein can be used as a biochemical indicator for early diagnosis of HIBD.(2)S100B protein was increased in the model of neonatal rat HIBD at 12 h, reached the peak 24 h, and then began to decrease.(3)TTC staining can be used as a important method to determine cerebral infarction. |
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