ABSTRACT
Objective To investigate the relationship between activation of gliacytes , mitogen-activated protein kinase (p38MAPK) and neuronal apoptosis after microinjecting aggregated Aβ25-35 into hippocampus.Methods The model was established by using stereotaxic technique to inject 10μg aggregated Aβ25-35 into dorsal hippocampus in rats .The rats were grouped as the control , vehicle and model groups .Immunohistochemistry and Western blotting were used for detection of activation of microglia(MG), atrocytes (AS) and expression of p-p38MAPK in the hippocampus.ELISA was used to evaluate the level of TNF-αand IL-1β.The survival neurons were observed by Nissl staining and the apoptotic neurons were identified by tunnel staining .Results Expression of ox-42, GFAP, p-p38MAPK were up-regulated in hippocampus, as well as TNF-α、IL-1β, which reached a highest value on the 7th day after injection of Aβ25-35.However, the number of neuron with Nissl positive decreased gradually , and the tunnel positive neurons increased highly and reached a peak value on the 7th day.There were significant differences between the control and vehicle group ( P <0.01). Conclusion Apoptosis of the neuron caused by Aβ25-35 injection may result from activation of gliacytes , p38 MAPK and increase of TNF-αand IL-1βlevel.
ABSTRACT
This study is to observe the effect of ilexonin A (IA) on the expression of basic fibroblast growth factor (bFGF) and growth associated protein-43 (GAP-43), and neurogenesis after cerebral ischemia-reperfusion in rats and explore its possible mechanism of protecting neuronal injury. Models of middle cerebral artery occlusion (MCAO) were established in SD rats. Before and after two hours ischemia-reperfusion, IA (20 and 40 mg x kg(-1)) was injected immediately and on 3, 7, 14, and 28 d once a day. The neurological severity was evaluated by neurological severity scores (NSS); neuronal injury in the boundary zone of the infarction area was evaluated by TUNEL and Niss1 staining. The expressions of bFGF and GAP-43 and neurogenesis were evaluated by Western blotting and 5-bromodeoxyuridine (Brdu) fluorescence staining, respectively. After treatment with IA, the NSS of treatment groups were lower than that of the models (3 and 7 d). The number of TUNEL positive neurons decreased and Nissl positive neurons increased at the same time (3 d). The expressions of bFGF and GAP-43 increased significantly in the boundary zone of the infarction area when compared to model group. Moreover, IA markedly enhanced the neurogenesis in the brain after ischemia-reperfusion, which revealed an increase of Brdu/NeuN positive cells in the boundary zone of the infarction area. The possible mechanism of protecting neuronal injury of IA may be related to inhibition on neuronal apoptosis, upregulation of bFGF and GAP-43, and neurogenesis in boundary zone of infarction after cerebral ischemia-reperfusion.
ABSTRACT
The probable mechanism of the reduction of rat cerebral ischemic-reperfusion injury by propyl gallate was studied. Intraluminal suture middle cerebral artery occlusion model of rat was employed. Propyl gallate was injected immediately after the ischemia was happened. The activity of NF-kappaB, and the expression of COX-2 and HSP70 on the peripheral ischemia were determined by Western blotting. The expression of TNF-alpha was determined by ELISA assay. RT-PCR and immunofluorescence staining were employed to detect the transcription and expression of TLR-4. Results showed that propyl gallate could inhibit the activity of NF-kappaB in the peripheral ischemia, and reduce the expression of COX-2 and TNF-alpha. As the upstream of NF-kappaB, the transcription and expression of TLR-4 decreased, as well as HSP70, the endogenic ligand of TLR-4. As an antioxidant, propyl gallate could reduce the cerebral ischemic-reperfusion injury through inhibiting the activity of NF-kappaB and decreasing the COX-2 and TNF-alpha in the peripheral ischemia. It also could influence HSP70 and TLR-4.