Time-course of mu-calpain activation, c-Fos, c-Jun, HSP70 and HSP27 expression in hypoxic-ischemic neonatal rat brain / 中华儿科杂志

<p><b>OBJECTIVE</b>The cascade of physiological events underlying hypoxic-ischemic brain damage (HIBD) remains to be fully established. The perinatal brain shows both an increased tolerance to hypoxic-ischemic (HI) injury and a faster and more complete recovery than the adult. It is, therefore, important to understand the sequence of events following hypoxia and ischemia in young animals. The present study aimed to clarify the time-course of the activation of the mu-calpain, and the expression of c-Fos, c-Jun, HSP70 and HSP27 proteins following severe HI (2 h hypoxia) and their relationship with each other.</p><p><b>METHODS</b>A modified newborn rat model of HIBD that included a combination of hypoxia and ischemia as described by Rice was used. Forty-two postnatal 7-day-old Sprague-Dawley rats were randomly divided into seven groups (6 rats in each): 6 time-window groups and a normal control group. Samples were collected at 0, 1, 2, 4, 12 and 24 h after HI insults. The protein concentration was determined using a modified Bradford assay. mu-calpain activation, c-Fos, c-Jun, HSP70 and HSP27 expressions were observed respectively by Western blot from cortical and hippocampal samples.</p><p><b>RESULTS</b>The cleavage of cytosolic mu-calpain was observed from both cortical and hippocampal samples in neonatal rats after HI. The ratio 76:80 of mu-calpain was increased significantly post-HI and reached a maximum at 24 h in cortex and at 12 h in hippocampus after HI. The expressions of c-Fos and c-Jun from both cortical and hippocampal samples in neonatal rats were up-regulated and peaked at 2 or 4 h after HI, demonstrating significant differences at 1, 2, 4, and 12 h compared with that observed in the control (P < 0.05). When compared with that observed in cortex, the nuclear c-Fos expression from hippocampal samples was highly elevated at 2, 4 and 12 h but significantly decreased at 24 h after HI (P < 0.05), while the nuclear c-Jun expression from hippocampal samples was highly elevated at 0 and 1 h but significantly decreased at 4 and 24 h after HI (P < 0.05). Similarly, the expressions of HSP70 and HSP27 from both cortical and hippocampal samples were up-regulated and reached a maximum at 12 or 24 h after HI, demonstrating significant differences at 12 or 24 h both in cortex and hippocampus for HSP70, and at 24 h in cerebral cortex as well as at 12 and 24 h in hippocampus for HSP27 compared with the control (P < 0.05). Furthermore, in comparison with that observed in cortex, the HSP70 expression from hippocampal samples was highly elevated at 1 h, but significantly decreased at 4, 12 and 24 h after HI (P < 0.05), while the HSP27 expression was permanently elevated in hippocampus after HI.</p><p><b>CONCLUSION</b>The neuronal injury induced by HI insults appears to involve many ongoing and simultaneous mechanisms. HI activates the calpains immediately, which may contribute to neuron apoptosis, and induces a significant brain neuroprotection, since there is an increased HSP70 expression and a relatively late remarkable HSP27 expression in hypoxic-ischemic neonatal rat brain. Nuclear c-Fos and c-Jun may participate in the pathogenesis of HIBD.</p>

Expression of brain-derived neurotrophic factor at acute inflammatory injury of the brain / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the expression of brain-derived neurotrophic factor (BDNF) mRNA and immunoreactivity in experimental acute inflammatory brain injury.</p><p><b>METHODS</b>Ten rats were inoculated with pneumococcus to establish the model of bacterial inflammatory brain injury and other 6 rats were used as normal controls. At 24 h after inoculating, the expression of BDNF mRNA and BDNF protein in brain tissue was detected by in situ hybridization and immunohistochemical methods, respectively.</p><p><b>RESULT</b>The necrosis of neuron in cerebral cortex and hippocampus was observed after infection. The increase of BDNF mRNA expression in the cerebral cortex and hippocampus of experimental animals was demonstrated at 24 h after inoculation: (0.1194 +/- 0.02941 compared with 0.0662 +/- 0.01176)A and (0.1608 +/-0.01854 compared with 0.0680 +/- 0.00946)A (P<0.01), respectively. Compared with controls the expression of BDNF protein in the cerebral cortex and hippocampus was enhanced at 24 h of inoculation:(177.04+/-43.66 compared with 79.79+/-7.23)mm(2) (P<0.01) and (81.78 +/-37.47 compared with 42.98 +/-20.44)mm(2) (P<0.01), respectively. Strong positive hybridization and immunoreactivity were observed in the infiltrated inflammatory cell in leptomeninges, subarachnoid cavity, ventricles and brain parenchyma in the brain from the experimental rats.</p><p><b>CONCLUSION</b>The expression of BDNF mRNA and BDNF protein increases following brain inflammatory injury, which supports the hypothesis that BDNF may constitute intrinsic neuroprotective mechanism as a part of the inflammatory response.</p>

Possible mechanism of electroacupuncture preconditioning for hypoxia/ischemic brain injury protection effect in neonatal rats / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To explore the possible mechanism of electroacupuncture preconditioning (EAPC) and combined with ATP-sensitive potassium channel (KATP) blocker preconditioning for hypoxia/ischemic brain injury protection by observing the changes of the immediate genes (c-fos and c-jun protein content) in brain at the early stage after cerebral hypoxia/ischemic injury, and the effect of EAPC on these changes.</p><p><b>METHODS</b>Integrated density (ID) of c-fos and c-jun expression was measured by Western blot and computerized image processing.</p><p><b>RESULTS</b>Hypoxia/ischemia could induce c-fos and c-jun protein in both cerebral cortex and hippocampus simultaneously, with the peak appearing 2-4 hrs later, and the expression in hyppocampus was higher than that in cortex. EAPC could lower KATP blocker induced permanent high expression in hyppocampus.</p><p><b>CONCLUSION</b>The effect of EAPC preconditioning in antagonizing cerebral hypoxia/ischemic injury may be related with its action in activating KATP, inhibiting the neuron apoptosis induced by the immediate genes at early stage of injury.</p>

A case-control study of risk factors for childhood cerebal palsy / 浙江大学学报·医学版

OBJECTIVE: To identify possible risk factors for cerebral palsy (CP) in children. METHODS: A Population-based survey was conducted (including 92 CP cases) in 66 townships of 15 cities of Zhejiang Province from October to November, 1998. 184 of matched controls were selected for comparison. RESULTS: Factors identified which were statistically significant for risk of subsequent childhood Cerebral Palsy included some neonatal diseases, some maternal diseases, low birth weight (<2500 g), maternal irregular menstruation, toxic, substances during pregnancy, malnutrition during pregnancy,and paternal age. CONCLUSION: Several risk factors for Cerebral Palsy were identified. Their prevention may result in redduction of the incidence of Cerebral Palsy.