Basic And Clinical Study On Myelin Basic Protein Following Cerebral Ischemia

PartⅠBasic Study on Changes of Myelin Basic Protein Following Global Cerebral IschemiaObjective To detect the changed axiom of myelin sheath and expression of myelin basic protein (MBP) in brain tissue following globle brain ischemia.Methods The whole-brain ischemia model of rats was established by the exposure of the brain of the healthy adult Sprague-Dawley rats to four-vessel occlusion (4-VO). To detect the changes of myelin sheath in corpus callosum by myelin staining and electron microscope and the changes of MBP expression in corpus callosum by immuneohisto -chemistry staining. The present study detected the expression of MBPmRNA and content changes of MBP in hippocampus by the methods of RT-PCR and ELISA.Results (1) The HE stain manifested that rarefaction, vacuolation, deep-stain glial cells and interstitial edema happened in corpus callosum at day 7 after globle brain ischemia. (2) Myelin staining of corpus callosum manifested that the array of myelinated fibres are tight in sham operated group. But, rarefaction and vacuolation were observed after brain ischemia. Compared to the sham operated group, the gray scale at day 7, 14 and 28 had significant difference (P<0.05). (3) Fine structure of myelin sheath in the sham operated group manifested axons were circumvolutioed by the myelin sheath with tight, uniformity and successive layers by the transmission electron microscope. However, deformation, light staining happened at day 7. Meanwhile, the diminished oligodendrocytes which contained less cytoplasmic organoids and oncotic mitochondria were also observed after brain ischemia. (4) Compared to the sham operated group, the MBP-positive fabric had significant difference at day 2 and 4 (P<0.05). (5) The expression of MBPmRNA in hippocampus of rats decreased at just day 2 after brain ischemia, but there was no significant difference compared with sham operated group (P>0.05). Which decreased significantly at day 7 (P<0.05) and which kept on decreasing at day 14 (P<0.01) and reached to the lowest level at day 28 (P<0.01). Compared with sham operated group, the expression of MBPmRNA decreased significantly at day 7, 14 and 28. The content of myelin basic protein (MBP) in the ischemic tissue decreased significantly at just day 2 after brain ischemia by the method of ELISA (P<0.05). Which decreased prominently at day 4 (P<0.01) and returned increaseingly at day 7 (P<0.01). This returned to control level at day 14. Compared to the sham operated group, the content of MBP had significant difference at day 2, 4 and 7.Conclusions (1) The affection on corpus callosum and hippocampus happened especially at day 7 after brain ischemia. (2) down-regulation of MBPmRNA was time- dependent in hippocampus following global ischemia with extention of reperfusion time.PartⅡClinical Study One Study on Feature and Prognosis of Different Classifications in Acute Cerebral InfarctionObjective To study the composition feature of different classifications such as The Trial of Org 10172 in Acute Stroke Treatment (TOAST) and Oxford Shire Community Stroke Project (OCSP) and relationships with the prognosis of acute infarction patients.Methods 164 ACI patients were classified into 5 and 4 groups based on the criteria of TOAST and OCSP. Meanwhile, all patients were scored according to the American National Institutes of Health stroke scale (NIHSS). The present study explored the relationships between the score and different subtypes.Results The constituent ratio of classification of TOAST was as follows: LAA was 17%, CE was 15.9%, SAO was 42.7%, SDE was 3.7% and SUE was 20.7%. In OCSP, TACI was 13.4%, PACI was 30.5%, POCI was 19.5% and LACI was 36.6%. The prognosis was the worst in CE and LAA, the consistency of unfavorable prognosis was 65.4% and 57.1%. SUE was 17.6%. SAO had the best prognosis, the consistency of prognosis was 0. Compared to SAO, the rate of unfavorable prognosis in CE and LAA had significant difference (P<0.0083). The prognosis of TACI was the worst in OCSP, the consistency of unfavorable prongosis was 90.9%. POCI and PACI were relatively better, the consistency of unfavorable prognosis were 28.1% and 24.0%. Compared to the SAO, the rate of unfavorable prognosis in TACI, PACI and POCI had significant difference (P<0.0083). Compared to the PACI and POCI, the rate of unfavorable prognosis in TACI had significant difference (P<0.0083).Conclusions The score of the patients in acute cerebral infarction varied with the different subtypes. TOAST and OCSP classification should be useful to prognosis of ischemic stroke as one of indexes.Two Clinical Study on Changes of MBP in Different Classifications of Acute Cerebral Infarction PatientsObjective To investigate the changes of serum level about MBP, TNF-αand IL-1β. To discuss the dependablity between MBP and NIHSS score, TNF-α, IL-1β.Methods 164 ACI Patients were classified into 5, 4 and 3 groups based on the criteria of TOAST and OCSP and were scored according to the NIHSS score. Meanwhile, conctrol group was established. The serum specimens were determinated by the method of ELISA. To analyze the dependablity between MBP and NIHSS score, TNF-α, IL-1β.Results (1) The serum levels of MBP, TNF-α, IL-1βin CE, LAA, and SUE increased after cerebral infarction, but, which had not significant changes in SAO. Compared to the control group and SAO, the serum levels of MBP, TNF-α, IL-1βin CE and LAA had significant difference (P<0.01). The serum levels of MBP, TNF-α, IL-1βin TACI, PACI and POCI in OCSP increased after cerebral infarction, but, which had not significant changes in LACI. Compared to the control group and LACI, the serum level of MBP, TNF-α, IL-1βin TACI, PACI and POCI had significant difference (P<0.01). Compared to the PACI and POCI, the serum level of MBP, TNF-α, IL-1βin TACI had significant difference (P<0.05). (2) To perform Correlations analysis between the serum level of MBP and NIHSS score in the different subtypes of ACI patients. Which indicated that there were positive correlations in LAA and SUE (r=0.68, 0.51; 0.62, 0.60) (P<0.05) in TOAST and there were positive correlations in TACI and PACI (r=0.62, 0.60) (P<0.05) in OCSP. (3) To perform Correlations analysis between the serum level of MBP and TNF-α, IL-1βin the different subtypes of ACI patients, which indicated that there were positive correlations in CE, LAA in TOAST (r=0.64, 0.56; 0.62, 0.52) (P<0.05) and there were positive correlations in TACI and PACI in OCSP (r=0.67, 0.57; 0.72, 0.66) (P<0.05).Conclusions Different classifications had different serum levels of MBP. There were positive correlations between MBP and NIHSS score in some subtypes. The serum levels of MBP were related to the severity of the state of cerebral infarction to some degree. The inflammatory factor include TNF-αand IL-1βmay involve in the elevation of MBP according to the injury of OLG indirectly and Blood Brain Barrier directly.