RESUMO
Objective To detecte the expressions of phosphorylated p38 MAPK (p-p38 MAPK), Bax and Bcl-2 in the cerebral cortex of hyperlipidemia rats after cerebral ischemia-reperfusion (I/R) injury and the effect of SB203580 on the expressions of p-p38 MAPK, Bax and Bcl-2, to explore the effect of p38 MAPK activation on the expressions of Bax and Bcl-2 in hyperlipidemia cerebral I/R injury. Methods After the hyperlipidemia model was established, the rats were randomly divided into 3 groups: sham operation group, operation group (I/R) and SB203580 treatment group (SB+I/R), with 10 rats in each group. The focal cerebral I/R model in hyperlipemia rats was established with thread embolism of the left middle cerebral artery. The neurobehavioral score was used to observe the symptoms of neurobehavioral injury. The 2, 3, 5-triphenyltetrazolium chloride (TTC) staining was used to detect the volume of cerebral infarction, and the TUNEL staining was used to observe apoptotic cells. The relative expression levels of p-p38 MAPK, Bax and Bcl-2 were analyzed by immunohistochemistry. Results Compared with the sham group, the infarct volume, apoptosis index and neurobehavioral score of rats in the I/R group increased significantly, and the expressions of p-p38 MAPK and Bax increased significantly, and the expression of Bcl-2 decreased significantly (P<0. 05). Compared with the I/R group, rats in the SB+I/R group had less brain damage, the infarct volume and the apoptosis index were significantly reduced, the expressions of p-p38 MAPK reduced significantly, Bax expression decreased while Bcl-2 expression increased. The differences were statistically significant (P<0. 05). Neurobehavioral scores were lower in SB+I/R group than in I/R group, but the difference was not statistically significant. Conclusion In the process of cerebral I/R injury in hyperlipidemiarats, activation of p38 MAPK can regulate the expression of Bax and Bcl-2.
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.