Effects of soybean isflavones on mitochondrial damage and neuronal apoptosis induced by cerebral ischemia/reperfusion

AIM: To study the effects of soybean isoflavones on mitochondrial ultrastructure, neuronal apoptosis and expression of cytochrome C, caspase-9 and caspase-3 in the rats with cerebral ischemia/reperfusion.METHODS: Adult healthy SD rats (n=60) were randomly divided into 3 groups: sham group, ischemia/reperfusion injury (I/R) group and soybean isoflavone (SI) pretreatment group. Soybean isoflavones (120 mg·kg-1·d-1) were fed by gastric lavage for 21 d. The global ischemia/reperfusion model of the rats was established by blocking 3 vessels, and then reperfused for 1 h after 1 h of ischemia. The morphological change of the cerebral cortex cells was observed under light microscope. The mitochondrial ultrastructure of the cerebral cortex cells was determined by transmission electron microscope. The apoptotic rate of the cerebral cortex cells was detected by flow cytometry. The expression of cytochrome C, caspase-9 and caspase-3 in the cerebral cortex cells was determined by semi-quantitative RT-PCR and immunohistochemical techniques.RESULTS: Disintegration of mitochondria membrane and disappearance of the mitochondrial cristae were seen in I/R group. Compared with I/R group, the change of ultrastructure of mitochondria was significantly improved by soybean isoflavone pretreatment, and the neuronal apoptotic rate was also significantly decreased (P<0.01). The mRNA expression and protein content of cytochrome C, caspase-9 and caspase-3 in I/R group were obviously higher than those in sham group (P<0.01). Compared with I/R group, the mRNA expression and protein content of cytochrome C, caspase-9 and caspase-3 in SI group were significantly decreased (P<0.01).CONCLUSION: Soybean isoflavones attenuate cerebral ischemia/reperfusion injury by stabilizing the structure of mitochondria, preventing cytochrome C release to the cytoplasm, inhibiting the activation of caspase-9 and caspase-3 and decreasing cell apoptosis．     

植物红景天对神经系统退行性病变作用的研究进展

红景天植物具有抑制脑细胞凋亡,提高神经元抵抗损伤的能力,对多种慢性退行性疾病具有显著的保护效应,用于治疗脑损伤以及神经退行性疾病。红景天具有多种药理作用,其活性强,药效明确,安全低毒,并且资源丰富,值得临床深入开发应用。就红景天对中枢神经系统退行性病变的保护作用及机制方面的研究进展做一综述。     

Clinical and pathological findings in a goat with cerebral gliomatosis

This report describes a buck with cerebral gliomatosis. The animal was severely apathetic to somnolent. Neurological examination revealed generalised ataxia and hyper-metria of the fore limbs. There was bilateral mydriasis and severely decreased menace and pupillary light reflexes. Sensitivity to pricking with a needle was markedly reduced over the entire body. There was a delayed response to adduction, abduction and crossing of the limbs and rocking of the animal. Examination of cerebrospinal fluid indicated mild mixed-cell inflammation. Based on all of the findings, an abscess or tumour of the central nervous system with localisation in the cerebrum was suspected. Because of the grave prognosis, the goat was euthanased and a post mortem examination performed. No macroscopic abnormalities were seen in any of the organs including the brain. Histologically, there was extensive diffuse glial cell hyperplasia in the white matter of the cerebral hemispheres and in the brain stem.     

Effect of nicotine against apoptosis of rat cortical neurons induced by colchicines

AIM:To explore the mechanism of nicotine against the apoptosis induced by colchicines in rat cortical neurons. METHODS:Cortical neurons were cultured from newborn Sprague-Dawley (SD) rats (less than 12 h). The rate of apoptosis was measured by Hoechst33258 fluorescence staining in the neurons, and the activity of Akt473 was analyzed by assay kit Akt473. RESULTS:The apoptosis of cortical neurons can be induced by 0.1 μmol/L colchicine. The phosphorlation of Akt 473 decreased significantly (1/3 times of the control group, P<0.01). However, when cortical neurons pretreated with 10 μmol/L nicotine for 2 h were cultured with 0.1 μmol/L colchicine for 24 h, the rate of apoptosis decreased from 62% to 38%. The phosphorlation of Akt473 increased significantly in a bell-shape time-dependent manner, which was respectively 1.3, 3.7, 2.4, 2.1 and 1.9 times compared with the control group (P<0.01). CONCLUSION:By activating the signal pathway of Akt473, nicotine may attenuate the apoptosis of cortical neurons induced by colchicines.     

The role of crocetin in protection following cerebral contusion and in the enhancement of angiogenesis in rats

The protective role of crocetin following cerebral contusion and its effects on the enhancement of angiogenesis in rats was investigated. A total of 60 Sprague–Dawley rats were divided into three groups (n = 20 each): crocetin therapy group (cerebral contusion treated with crocetin), cerebral trauma control group (without treatment), sham operation control group. The effect of crocetin was examined by modified Neurological Severity Scores (mNSS), electron microscopy, terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) procedure, western blotting analysis of Bcl-2 protein expression, microvessel count (MVC), endothelial cell culture and immunocyto-chemistry. The mNSS results indicated that neurological function of therapy group was significantly recovered seven days and fifteen days after the trauma. The TUNEL staining and electron microscopy revealed that crocetin treatment led to an inhibition of neuronal apoptosis 72 h following treatment; this finding was confirmed by western blot analysis of B cell lymphoma/leukemia-2 (Bcl-2) protein expression. Expression levels of vascular endothelial growth factor receptor-2 (VEGFR-2) and serum response factor (SRF) were higher in the crocetin therapy group in comparison to the two other experimental groups. Our results demonstrate that the protective effects of crocetin upon brain injury may be related to its ability to inhibit apoptosis at early stages of the injury and its ability to promote angiogenesis at the sub-acute stage.     

绿色饲料添加剂——大蒜

随着生活水平的提高，小康社会生活标准越来越深入人心，成为人们的需求和向往，控制药物残留、人畜共患传染病，是绿色食品、绿色饲养、绿色认证的必检项目，开发绿色饲料添加剂，生产绿色安全的畜禽产品，杜绝药物残留、消灭传染病保持动物生态平衡成为动物科学的日事议程。现介绍天然的饲料添加剂——大蒜。     

Changes and significance of ATPase and free radical in aged rats with brain ischemia-reperfusion

AIM: To study the mechanism of brain ischemia-reperfusion injury from ATPase activity and free radical metabolism in aged rats. METHODS: The young rats (5 months) and the aged rats (more than 20 months) were divided into young control group(YCG), young model group(YMG), aged control group(ACG) and aged model group(AMG). The ATPase and SOD activities and the contents of MDA, Ca^2＋, Na^＋ and K^＋ were measured in the rats with 30 min brain ischemia followed by 60 min reperfusion. RESULTS: The Ca^2＋content in the AMG was higher than that in the YMG and the ACG. The Na^＋-K^＋-ATPase activity in the ACG was lower than that in the YCG,was lower in the AMG than that in the YMG. The Ca^2＋-ATPase activities in the YCG was higher than that in the ACG, was lower in the AMG than that in the YMG and was higher than the ACG's. The serum and brain tissue SOD activities in the ACG was lower than that in the YCG, was lower in the AMG than YMG 's. The serum and brain tissue MDA/SOD ratio in the AMG was higher than that in the ACG.CONCLUSION:The brain tissue ischemia-reperfusion injury was related with calcium overload and free radical injury.The pathological changes were obvious and had some characteristics in the aged rats compared with the young rats because of the brain t issue aging changes in ATPase,calcium content and free radical metabolism in the aged rats.     

Changes in platelet-activating factor receptor binding characteristics in cerebral thrombotic core and penumbra of tree shrews

AIM: To observe the changes in platelet-activating factor (PAF) receptor binding characteristics and explore the action of PAF on formation of thrombotic core and penumbra following local cerebral ischemia. METHODS: Neuron's membrane protein was abstracted, and the local cerebral ischemia model were induced by photochemistry in tree shrews. The PAF binding sites on central neuron membrane were studied by-PAF binding assay. RESULTS: There were two different affinities of PAF receptors on tree shrew's brain cell membrane, with kD₁=(3.61 ±0.72) nmol/L and kD₂=(17.04±2.41) nmol/L, corresponding respectively to maximum number of binding sites: B_max1=(1 457.94±168.01) pmol/g protein and B_max2=(5 017.40±742.16) pmol/g protein. The binding sites decreased in ischemic core, penumbra and contralateral regions at 4,24 and 72 h after ischemia (P<0.01), with those of 24 h reaching the minimum levels. CONCLUSION: PAF receptors play an important role in cerebral ischemia, may be related to the secondary damage in ischemic penumbra, and also are molecular bases of brain injury induced by PAF.