Puerarin Up-regulates Methyl-CpG Binding Protein 2 Phosphorylation in Hippocampus of Vascular Dementia Rats / 中国结合医学杂志

<p><b>OBJECTIVE</b>To observe the effect of puerarin on methyl-CpG binding protein 2 (MeCP2) phosphorylation (pMeCP2) in the hippocampus of a rat model of vascular dementia (VD).</p><p><b>METHODS</b>Thirty-six healthy Sprague-Dawley rats were randomly assigned to the sham-operated group, dementia group and puerarintreated group using a random number table (n=12 per group). The modifified permanent bilateral common carotid artery occlusion method was used to establish the VD model. The sham-operated and dementia groups were given 2 mL/d of saline, while the puerarin-treated group was given 100 mg/(kg•d) of puerarin for 17 days. The learning and memory abilities were evaluated by the Morris water maze test. Hematoxylin-eosin staining, immunohistochemical (IHC) staining and Western blot analysis were carried out to observe changes in neuron morphology and in level of pMeCP2 in the hippocampus, respectively.</p><p><b>RESULTS</b>The morphologies of rat hippocampal neurons in the puerarintreated group were markedly improved compared with the dementia group. The escape latency of the dementia group was significantly longer than the sham-operated group (P<0.05), while the puerarin-treated group was obviously shorter than the dementia group (P<0.05). Cross-platform times of the dementia group were signifificantly decreased compared with the sham-operated group (P<0.05), while the puerarin-treated group was obviously increased compared with the dementia group (P<0.05). IHC staining showed no significant difference in the number of MeCP2 positive cells among 3 groups (P>0.05). The number of pMeCP2 positive cells in the CA1 region of hippocampus in the dementia group was signifificantly increased compared with the sham-operated group, and the puerarin-treated group was signifificantly increased compared with the dementia group (both P<0.05). Western blot analysis showed no signifificant difference of MeCP2 expression among 3 groups (P>0.05). The expression of pMeCP2 in the dementia group was signifificantly increased compared with the sham-operated group, while it in the puerarin-treated group was signifificantly increased compared with the dementia group (P<0.05).</p><p><b>CONCLUSION</b>Puerarin could play a role in the protection of nerve cells through up-regulating pMeCP2 in the hippocampus, improving neuron morphologies, and enhancing learning and memory ablities in a rat model of VD.</p>

Effects of recombinant human erythropoietin on brain-derived neurotrophic factor expression in different brain regions of aging rats / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the effect of recombinant human erythropoietin (rhEPO) on expression of brain-derived neurotrophic factor (BDNF) in different brain regions of aging rats.</p><p><b>METHODS</b>Forty male SD rats were randomized equally into negative control group, D-galactose group, EPO treatment group, and positive control group. Rat models of subacute aging were established by continuous subcutaneous injection of 5% D-galactose. Immunohistochemical staining was used to analyze the variation of BDNF expressions in different brain regions of the aging rats with different treatments.</p><p><b>RESULTS</b>Significant brain region-specific differences in BDNF expression were found among the rats in different groups. Compared with those in the negative control group, the numbers of BDNF-positive cells in the hippocampal CA1 region, CA3 region, dentate gyrus (DG) and frontal cortex were all decreased obviously in D-galactose group (P<0.05) but increased in both EPO group and the positive control group (P<0.05) without significant differences between the latter two groups. In the rats in the same group, the number of BDNF-positive cells varied markedly in different brain regions (P<0.05), and the expression level of BDNF was the highest in the frontal cortex followed by the hippocampal CA3 region and the dentate gyrus, and was the lowest in the hippocampal CA1 region.</p><p><b>CONCLUSION</b>Treatment with rhEPO enhances the expression of BDNF in rat neural cells, suggesting that rhEPO may protect the nervous system from aging by regulating the BDNF pathway.</p>

Characteristic of microglial activation of hippocampus in experimental epileptic rats / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the characteristics of microglial activation of hippocampus in experimental epileptic rats.</p><p><b>METHODS</b>Morphological changes and proliferation of OX-42 positive cells were compared at different time points after status of epilepticus (SE) in lithium-pilocarpine induced epileptic rats.</p><p><b>RESULTS</b>OX-42 positive cells were activated after SE, which increased to a peak at 3-7 d and in a relatively stable state at 7-14 d; then gradually decreased after 14d and returned to slightly higher level than previously at 21 d.</p><p><b>CONCLUSION</b>Inflammatory injury, microglial activation and cell proliferation are closely related after seizures, microglial activation may be an important mechanism in the inflammatory injury of epilepsy.</p>

Effect of Helicobacter pylori infection on platelet activation and coagulation function in patients with acute cerebral infarction / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effect of Helicobacter pylori (Hp) on platelet activation and coagulation function in patients with acute cerebral infarction.</p><p><b>METHODS</b>Sixty-six patients with acute cerebral infarction and 50 health individuals were enrolled in the study. Hp antibody,expression of CD62p on platelets and clotting indexes were measured and compared between two groups.</p><p><b>RESULTS</b>The positive rate of Hp-IgG and Hp-CagA in cerebral infarction patients were higher than that in controls (P<0.05). The positive rate of CD62p in patients with positive Hp-IgG and Hp-CagA was significantly higher than that in negative patients and also controls (P<0.05). The APTT and TT were lower and FIB was higher in patients with positive Hp antibody than those in patients with negative Hp antibody (P<0.05),but there was no difference in PT,PTR and INR (P>0.05).</p><p><b>CONCLUSION</b>Hp infection can activate platelets and affect coagulation function,which may be involved in the development of cerebral infarction.</p>

Protective effect of puerarin against calcium overload after focal cerebral ischemia injury in rats / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the temporal and spatial changes in the distribution of Ca2+ in the rat brain following focal cerebral ischemia injury and explore the protective effect of puerarin against calcium overload.</p><p><b>METHODS</b>Focal cerebral ischemia was induced by middle cerebral artery occlusion in rats. After cerebral ischemia, puerarin was administered in the rats at different time points. The volume of ischemic cerebral tissue was assessed by TTC staining, and the fluorescence intensity of Ca2+ in the cortex and corpora striata was determined under laser scanning confocal microscope.</p><p><b>RESULTS</b>The fluorescence intensity of Ca2+ in the infracted cortex and corpora striata begun to increase 2 h after the ischemia and was further enhanced with the prolongation of the ischemic time. No significance was found in the fluorescence intensity of Ca2+ between the cortex and corpora striata. The fluorescence intensity of Ca2+ in the infarcted corpora striata was obviously higher than that in the cortex after ischemia. Compared with that in the ischemic model group, the fluorescence intensity of Ca2+ in the infarcted cortex and corpora striata decreased significantly at 2 and 12 h following puerarin intervention (P<0.05).</p><p><b>CONCLUSION</b>Puerarin treatment can relieve calcium overload, reduce cerebral ischemic volume and play a neuroprotective role against focal cerebral ischemia. Twelve hours following cerebral ischemic injury may be the time window for administering puerarin intervention.</p>

Expression of glucose transporter-3 in the cerebral cortex of aging rats / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the changes in the expression of glucose transporter-3 (GLUT3) in the cerebral cortex of rats during aging and investigate the role of GLUT3 in the aging process of the nervous system.</p><p><b>METHODS</b>The cerebral tissues were collected from rats of 3, 18, 24, and 30 months old (10 in each age group), and the expression of GLUT3 in the cerebral cortex was detected by immunohistochemistry.</p><p><b>RESULTS</b>Under optical microscope, GLUT3-positive cells were found in every group. Within the age range of 3 to 8 months, GLUT3-positive cells increased significantly with age (P<0.01), but at 24-30 months of age, the number of GLUT3-positive cells reduced significant with age (P<0.01).</p><p><b>CONCLUSION</b>The expression changes of GLUT3 ir the cerebral cortex of rats during aging indicate that GLUT3 plays an important role in the maturation and aging of the nervous system.</p>

Expression of vascular endothelial growth factor and microvessel density in hippocampus of rats with aging / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the expression of vascular endothelial growth factor (VEGF) and microvessel density (MVD) in hippocampus of rats with aging.</p><p><b>METHODS</b>Paraffin sections of brain tissue of rats at the age of 3, 18, 24, 30 months were stained by immunohistochemistry, the expression of VEGF and MVD was quantitatively analyzed.</p><p><b>RESULTS</b>Innunohistochemical staining showed that the VEGF-positive cells were mainly pyramidal neuron in hippocampus; the intensity of VEGF-positivity in neuron cells was decreased with the aging (P<0.05). The MVD in hippocampus was also decreased with the aging of rats (P<0.05).</p><p><b>CONCLUSION</b>Increasing VEGF contents and improving blood circulation in brain tissue may prevent or treat vascular dementia and cerebrovascular diseases.</p>

Expression of GLUT 3 in different brain regions of aged rats / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To examine the distribution of glucose transport 3 (GLUT 3) in different brain regions of aged rats and to investigate its role in ageing process of the nervous system.</p><p><b>METHODS</b>The GLUT 3 expression in different brain regions was examined with immunohistochemical method in rats aged 3, 18 and 30 months, respectively.</p><p><b>RESULTS</b>The number of GLUT 3-positive cells varied in the different brain regions in rats of all age groups (P<0.01); the CA1 region contained the greatest number of positive cells,and fewer in the motor cortex and cerebellum. The number of GLUT 3-positive cells was reduced in the brain of aged rats (P<0.01); and the neural cells in 4 different brain regions presented with large cell body and loose alignment.</p><p><b>CONCLUSION</b>The expression of GLUT 3 decreased in aged rats, which suggests that GLUT 3 may be involved in the ageing process of nervous system.</p>

Protective effects and mechanism of puerarin on learning-memory disorder after global cerebral ischemia-reperfusion injury in rats / 中国结合医学杂志

<p><b>OBJECTIVE</b>To observe the effect of puerarin on the learning-memory disorder after global cerebral ischemia-reperfusion injury in rats, and to explore its mechanism of action.</p><p><b>METHODS</b>The global cerebral ischemia-reperfusion injury model was established using the modifified Pulsinelli four-vessel occlusion in Sprague-Dawley rats. Rats were intraperitoneally injected with puerarin (100 mg/kg) 1 h before ischemia and once every 6 h afterwards. The learning-memory ability was evaluated by the passive avoidance test. The dynamic changes of the cell counts of apoptosis and positive expression of Bcl-2 in the hippocampus CA1 region were determined by the TUNEL and immunohistochemical methods, respectively.</p><p><b>RESULTS</b>(1) Compared with the reperfusion group, the step through latency (STL) in the passive avoidance test in the puerarin group was prolonged signifificantly (P<0.01). (2) The apoptotic neurons were injured most severely on the 3rd day in the hippocampal CA1 region after global ischemia and reperfusion. In the puerarin group, the number of apoptotic cells decreased at respective time points after ischemia-reperfusion (P<0.01). (3) The level of positive expression of Bcl-2 varied according to the duration of reperfusion and the peak level occurred on day 1 in the hippocampal CA1 region after global cerebral ischemia. Compared with the reperfusion group, the expression of Bcl-2 in the puerarin group was up-regulated at the respective time points after ischemia reperfusion (P<0.01), reaching the peak on day 1.</p><p><b>CONCLUSIONS</b>Puerarin could improve the learning-memory ability after global cerebral ischemia and reperfusion in rats. The protective mechanism might be related to the effect of inhibiting or delaying the cell apoptosis through up-regulating the expression of Bcl-2 after ischemia and reperfusion.</p>

Expression of hypoxia inducible factor-1alpha in different brain regions in aged rats / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the distribution of hypoxia inducible factor-1alpha (HIF-1alpha) in different brain regions in aged rats and investigate the role of HIF-1alpha in the aging process of the nervous system.</p><p><b>METHODS</b>The Nissl bodies and HIF-1alpha expression in different brain regions were observed in rats aged 3 and 30 months using Nissl staining and immunohistochemical method, respectively.</p><p><b>RESULTS</b>In the 30-month-old rats, the neural cells in 4 different brain regions presented with large cell body and loose alignment, containing reduced Nissl bodies in the cytoplasm. Compared with the 3-month-old rats, the aged rats showed greater number of HIF-1alpha-positive cells in the brain (P < 0.01), and the number varied significantly between the different brain regions (P < 0.01). The CA3 region contained the greatest number of positive cells, which were fewer in the motor cortex and cerebellum.</p><p><b>CONCLUSION</b>The capacity for protein synthesis in the neural cells is weakened but the expression of HIF-1alpha increased in aged rats, suggesting the important role that HIF-1alpha may play in the aging process of the nervous system, especially in hypomnesis.</p>