ABSTRACT
Objective To investigated the neuroprotective effect of PTEN inhibitor BPV on cerebral ischemia-reperfusion injury in rats and its mechanism. Methods Male Sprague-Dawley rats were used to induce a reperfusion model of middle cerebral artery occlusion for 1 h. During the reperfusion, the BPV solution (0. 2 mg/kg daily) or the equal volume of saline was injected intraperitonealy immediately. The neurological deficit scores were conducted at day 1, 3,5, and 7 after ischemia-reperfusion. At day 4, triphenyl tetrazolium chloride staining was used to assess cerebral infarction volume. Enzyme-linked immunosorbent assay was used to detect the levels of interleukin 10 (IL-10) and tumor necrosis factor α(TNF-α) in cortical ischemic border zones. Real-time quantitative polymerase chain reaction was used to detect the expression level of PTEN mRNA. Western blotting was used to detect the expression levels of PI3K, Akt, and p-GSK-3β. At day 7, Bielschowsky silver staining was used to detect the axonal distribution in the ischemic border zone of the striatum. Immunohistochemical staining was used to detect the expression of myelin basic protein (MBP). Results At day 4 after ischemia-reperfusion, the infarct volume (32. 27% ± 1. 71% vs. 45. 49% ± 2. 12% ; P < 0. 001), TNF-α concentration in the cortical ischemic border zones (134. 17 ± 10. 38 pg/ml vs. 264. 17 ± 24. 84 pg/ml; P < ), and PTEN mRNA level (1. 19 ± 0. 08 vs. 2. 50 ± 0. 06; P < 0. 001) in the rats of the BPV group were al significantly lower than those of the normal saline group. The IL-10 concentration (186. 83 ± 10. 83 pg/ml vs. 147. 83 ± 11. 62 pg/ml; P < 0. 001), and the expression levels of PI3K (0. 43 ± 0. 08 vs. 0. 26 ± 0. 06; P = 0. 004), Akt (0. 52 ± 0. 05 vs. 0. 40 ± 0. 04;P = 0. 001), and p-GSK-3β (0. 75 ± 0. 08 vs. 0. 38 ± 0. 06; P < 0. 001) were al significantly higher than those of the normal saline group. At day 7 after ischemia-reperfusion, the neurological deficit score (4. 83 ± 0. 41 vs. 6. 33 ± 0. 52; P < 0. 001) in the rats of the BPV group was significantly lower than that of the normal saline group. The axon densities in the ischemic border zones (35. 51% ± 2. 45% vs. 25. 31% ± 2. 79% ; P < 0. 001) and the expression level of MBP (32. 56% ± 3. 46% vs. 27. 81% ± 4. 18% ; P = 0. 037) were significantly higher than those of the normal saline group. Conclusions BPV has neuroprotective effect for cerebral ischemia-reperfusion injury in rats. Its mechanism may be associated with the up-regulation of PTEN downstream proteins PI3K, Akt and p-GSK-3β expression to regulate inflammatory mediators and reduce the inflammatory response.
ABSTRACT
Objective:To study the reliability and feasibility of intranasal(IN)pathway bypassing the blood-brain barrier (BBB) and observe the potential neuroprotective effects of intranasal NGF on acute cerebral ischemia. Methods:A blinded, vehicle-controlled study of IN NGF and IV NGF administration was performed by intraluminal middle cerebral artery occlusion (MCAO) model. Experiment 1: Rats were randomly divided into IN NGF, IV NGF and untreated group (n=4). The concentration of NGF in different brain regions was measured by ELISA. Experiment 2: Rats were randomly assigned into 4 groups: IN vehicle, IN NGF, IV vehicle, IV NGF (n=8 each). Treatments was initiated 30 min after the onset of MCAO and then again 24 h later. Three neurologic behavioral tests were assessed at 24 h and 48h. Corrected infarct volumes were determined 48 h after the onset of MCAO. Results:Olfactory bulb in IN NGF group obtained the highest concentration among all tissues, arriving at 3 252 pg/g, followed by hippocampus. The NGF concentrations of olfactory bulb and hippocampus in IN NGF group were significantly higher than that in IV NGF and control group. The infarct volume in IN NGF group was reduced significantly by 38.8% as compared with IN vehicle. The vestibulomotor function of IN NGF improved significantly at 24 and 48 h (P=0.02 and P=0.04, respectively). Conclusion:Intranasal NGF could bypass BBB, reach the CNS, reduce infarct volume and improve neurological function in rats following MCAO. Intranasal delivery of NGF holds a promising treatment for stroke and other CNS disorders.