RESUMO
Objective To observe the effect of polyinosinic-polycytidylic acid ( Poly-IC ) treatment on the expressions of Bcl-2 and Bax after cerebral ischemia-reperfusion ( I / R ) injury in fryperlipidemia rats, and to detect the cerebral infarction, blood-brain barrier permeability and behavioral injury symptoms, to explore the neuroprotective effect of Poly-IC treatment on cerebral I /R injury in fryperlipidemia rats. Methods Hyperlipidemia rats were randomly divided into cerebral I /R group, Poly-IC pretreatment group, Poly-IC post-treatment group and sham operation group, 20 rats in each group. Neurobehavioral performance of rats in each group was recorded according to neurobehavioral score of 0-4 points. Blood-brain barrier permeability of rats in each group was detected by Evans blue staining. TTC staining was used to observe the cerebral infarction in each group. Apoptotic cells in the cerebral cortex of rats in each group was observed by TUNEL staining. The relative expression levels of Bcl-2 and Bax were determined by Western blotting. Results Compared with the sham group, the symptoms of neurobehavioral damage in the I/R group were serious and the score increased significantly (P<0. 05). The scores of Poly-IC pretreatment and post-treatment groups were significantly lower than that of I/R group (P<0. 05). Evans blue staining result showed that the blood-brain barrier permeability of the I/R group was significantly higher than that of the sham group (P<0. 05) , and Poly-IC pretreatment or post-treatment could significantly reduce the blood-brain barrier permeability ( P < 0. 05 ) . No infarct was observed in the sham group with uniform red staining, while white infarct was observed in the brain tissue of the I/R group. Compared with the I/R group, the volume of infarct in both Poly-IC pretreatment and post-treatment groups reduced significantly (P<0. 05). The apoptosis index in cerebral cortex of rats in I/R group was significantly higher than that in sham group ( P < 0 .05 ) , while the apoptosis index in Poly-IC pretreatment or post-treatment group was significantly lower than that in I/R group(P<0. 05 ) . The result of Western blotting showed that, compared with the sham group, the expression of Bax in the I/R group was significantly increased(P<0. 05) , the expression of Bcl-2 was significantly decreased(P<0. 05). Compared with the I/R group, the expression of Bax in the Poly-IC pretreatment or post-treatment group reduced significantly ( P < 0. 05 ) , the expression of Bcl-2 increased significantly(P<0. 05). Conclusion Poly-IC pretreatment or post-treatment can improve the symptoms of neurobehavioral injury, reduce the damage of blood-brain barrier, reduce the volume of cerebral infarction, decrease the apoptosis index of nerve cells, play a neuroprotective effect on cerebral ischemia reperfusion injury in rats with hyperlipidemia, and this protective effect may be related to the change of Bcl-2 and Bax expression levels.
RESUMO
Objective To explore the neuroprotective role of Genistein (GEN) on hippocampal CA1 neurons and the possible mechanism following global cerebral ischemia ( GCI) in rats.Methods Seventy five rats were subjected to global cerebral ischemia ( GCI ) by four-vessel occlusion and randomly divided into five groups , sham, ischemia/reperfusion (I/R), GEN, ICI 182,780 and vehicle groups.Fluoro-Jade B and neuron-specific nuclear-binding protein ( NeuN) staining was used to observe CA 1 neuronal survival .TUNEL was used to detect apoptotic neurons .Spatial learning and memory function of the rats were evaluated by Morris water maze .Results The best dose of neuroprotective role of GEN was 1.0mg/kg body weight.Compared with sham, TUNEL-positive neurons in the hippocampal CA1 region increased significantly in I/R and vehicle groups (P<0.01), while post-treatment with GEN (1.0mg/kg) at 5min after ischemia by tail vein injection decreased markedly (P<0.01).Treatment of 1.0mg/kg GEN markedly attenuated spatial learning and memory deficits of the rats after ischemic insult compared to I /R group.Furthermore, ICI 182,780 significantly abolished the neuroprotective role of GEN (P <0.01).Conclusion The low-dose (1.0mg/kg) GEN significantly attenuates neuronal damage and cognitive deficits following GCI in rats , and the mechanism may be involved in estrogen receptor activity.