[Effect of puerarin on the expression of NMDA receptor in the hippocampus CA1 region after focal cerebral ischemia in rats].

OBJECTIVE: To study the antagonistic action of Puerarin against the excitatory amino acid toxicity, and to further explore its brain protection mechanisms. METHODS: Focal cerebral ischemia model was set up with middle cerebral artery occlusion by intraluminal block in this study. After cerebral ischemia, Puerarin was administered at different time point. The volume of cerebral ischemia was assessed by TTC stain. NR1 positive neurons in hippocampus CA1 region was determined by immunohistochemistry SABC method. RESULTS: The cerebral ischemia volumes were smaller in 2 h and 12 h model treatment groups (P < 0.05) than those in model control groups, but no significant differences were observed in 24 h model treatment group. Compared with sham-operation group, the NR1-positive cells in hippocampal CA1 region were increased obviously (P < 0.05) in both model control and model treatment groups. Compared with model control groups, the NR1-positive cells in hippocampal CA1 were decreased obviously (P < 0.05) in 2 h and 12 h treatment groups. CONCLUSION: The treatment of Puerarin within 12 h after ischemia can cut down the expression of NMDA receptor. This indicates that the puerarin treatment in earlier period after ischemia can indirectly rivalry toxic effect of excitatory amino acids, relieve neural injury.

[Protective effect of puerarin against calcium overload after focal cerebral ischemia injury in rats].

OBJECTIVE: 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. METHODS: 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. RESULTS: 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). CONCLUSION: 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.

[Expression of hypoxia inducible factor-1alpha in different brain regions in aged rats].

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.