NBP Promote Activation Of Functional Down-regulation Area In Rats With Cerebral Infarction:Temporal Assessment With DTI

Backgroud and PurposeThrough evaluated ischemic area and cerebral area of functional downregulation by DTI in rats, to explore the relation with RGMa protein expression, and to further explore the NBP promote axonal regeneration of ischemic area and functional down-regulation area via downregulation of RGMa protein expression, thus improving the recovery of nerve function and the changes of imaging findings in rats. Materials and Methods:1. 140 healthy male SD rats were randomly divided into following four groups: sham operation group, MCAO model group, saline group and the experimental group. MCAO model was made by line bolt. The rats of experimental group intraperitoneal injection of butyl phthalide drugs after ischemia, drugs dose was calculated at 80mg/kg; the rats of normal saline group were given same volume of physiological saline. Each group would be further divided into 5 subgroups(1h, 3h,6h, 12 h, 24h).2. 20 SD rats were randomly selected(sham group, MCAO modle group, saline group,NBP group; 5 rats of each group), the magnetic resonance exam and modified neurological severity scores were performed at 1h, 3h, 6h, 12 h, 24 h after successful MCAO model. Using the American GE Discovery MR 750 3.0T high-field magnetic resonance instrument and special coil of rats. The rats was fixed in supine position, and the optic chiasm was the center of scan. The conventional axial T1-weighted imaging(T1WI) and T2-weighted imaging(T2WI), axial DWI and DTI were perfomed. Calculate the apparent diffusion coefficient(ADC) and fractional anisotropy( FA) of lesion side and cerebellar hemisphere.3. 60 SD rats were randomly selected(sham group, MCAO modle group, saline group,NBP group; 15 rats of each group), Western blot assay RGMa expression of ischemia side and cerebellum at 1h, 3h, 6h, 12 h, 24 h after MCAO model; in addition 60 SD rats(15 rats of each group), semi-quantitative immunohistochemical analysis of RGMa and NF-200 protein.4. All datas applications SPSS 17.0 software for statistical analysis, and the quantitative data was expressed as mean ± standard deviation. Test methods were t-test, repeated measures analysis of variance, one-way ANOVA, Spearmen correlation analysis, testing standards for ? = 0.05, P < 0.05 indicated statistically significant. Results:1. The Modified Neurological Severity Score(mNSS) of MCAO model group, saline group, butylphthalide group were higher than sham group, mNSS were more higher over time; at 3h, 6h, 12 h, at 24 h after ischemia, mNSS of NBP group compared with MCAO model group, the difference was statistically significant(P < 0.05).2. MCAO model group, saline group after ischemia 1h, the ADC values and FA values of ischemic area begun to decrease, and increased to minimum and at 12 h after ischemia; ischemic area ADC values, FA values of styrene-butadiene phthalocyanine group compared with MCAO model group at 3h, 6h, 12 h, 24 h after ischemia, the difference was statistically significant. After ischemia 1h, the cerebellum ADC values, FA values of MCAO model group and saline group decrease compared with sham group, and had significant difference(P < 0.05); The cerebellum ADC values, FA values of NBP group compared with MCAO model group at 12 h or 24 h, differences between the two groups was statistically significant; at 3h, 6h, 12 h, 24 h after ischemia, FA value of the difference between the two groups was statistically significant( P < 0.05).3. After ischemia, RGMa protein expression of MCAO model group and saline group in ischemic area had increased, which were staining with brownish yellow. RGMa expression gradually increased over time, up to maximum at 12h; RGMa protein expression of NBP group were decreased, the difference between NBP group and MCAO group had statistically significant at 6h, 12 h, 24h; RGMa protein expression changes between cerebellum and ischemic area were similar, RGMa protein expression of NBP group were reduced, difference was statistically significant at 1h, 3h, 6h, 12h(P < 0.05).4. At 3h after ischemia, NF-200 protein expression in the ischemic area and cerebellum of MCAO model group and saline group were reduced, which were staining with brownish yellow. NF-200 expression decreased over time; NF-200 expression of NBP group were increased, the difference between the two groups was statistically significant at 6h, 12 h and 24h(P < 0.05).5. FA value of ischemic area had negative correlation with mNSS, and RGMa protein expression of ischemic area had positive correlation with mNSS. Conclusion1. The RGMa upregulated expression of cerebral infarction area involved in nerve function impairment in rats;2. NBP promoted activation of functional down-regulation area in rats with cerebral infaration via downregulation of RGMa gene expression, and thus play a neuroprotective effect after cerebral infarction;3. The DTI could dynamically monitor changes in rats with ischemic stroke and changes after treatment.