| Objective: To investigate the effects of ephedrine combined with various doses of naloxone on neural plasticity and to find an optimal dose of naloxone in rats after cerebral ischemia/reperfusion injury for the clinical application of the treatment of cerebral ischemic disease to provide more reliable theoretical basis.Methods: 180 Sprague-Dawley (SD) rats, weighting 220-250 g, were used to prepare left middle cerebral artery occlussion (MCAO)models by using modified Longa ligation. They were randomly divided into 8 groups: model group, ephedrine treatment group, low-dose naloxone treatment group, meta-dose naloxone treatment group, high-dose naloxone treatment groups, ephedrine + low-dose naloxone treatment group, ephedrine + meta-dose naloxone treatment group, ephedrine + high-dose naloxone treatment group. 1 week of preoperative training for walking beam test before operation so that it is up to 6 sub-levels; after 1,2,3,4 weeks beam walking test detected sensorimotor integration; HE staining ipsilateral hippocampal cell morphology Change; deteted the experssion of Brain-derived neurotrophic factor (BDNF) on hippocampal cells by immunofluorescence method; detected the dynamic changes of expression growth associated protein-43 (GAP-43), synaptophysin (SYP),β-endorphin (β-EP) by immunohistochemistry; TUNEL staining of hippocampal cell apoptosis.Results:1. Sensorimotor integration (BWT): At 1-3 weeks of ephedrine group scored significantly higher than the model group, P <0.05, three doses of naloxone group compared with model group, no significant difference , P > 0.05; in all ephedrine + naloxone treatment group, with the dose of naloxone increased, scored higher at the corresponding time points;2. Hippocampal cell morphological changes (HE staining): the model group, large areas of necrosis of hippocampal nerve cells, neuron reduction neuronal karyopyknosis and significant glial hyperplasia were pbserved. In each treatment groups, tissue construction was distinct, neuron were relatively dense;3. BDNF(immunofluorescence): in the ephedrine and ephedrine + naloxone treatment groups the expression of BDNF is higher than the model group, the expression of BDNF highest in the ephedrine + high-dose naloxone group at the 2, 3 weeks, compared with model group, the difference is statistically significant;4. GAP-43(immunohistochemistry):in the ephedrine and ephedrine + naloxone treatment groups, the level of GAP-43 is higher than the model group, ephedrine + high-dose naloxone group expressed the highest at 2,3 weeks, the difference is statistically significant;5. SYP(immunohistochemistry): the expression of SYP higher than the model group in the ephedrine and ephedrine + naloxone treatment groups, ephedrine + high-dose naloxone group to express the highest and have statistically significant difference at 2, 3 weeks, compared with model group;6.β-EP(immunohistochemistry): the expression ofβ-EP in the ephedrine and ephedrine + naloxone treatment groups was significantly lower than model group at 2, 3 weeks, ephedrine + high doses of naloxone group keep theβ-EP continued to be low expression, differences with statistical significance;7. Apoptosis (TUNEL staining): at 1 week, the number of hippocampal cell apoptosis increased in the the model group, and then gradually reduced over time, the number of apoptotic cells in the ephedrine and ephedrine + naloxone treatment groups was significantly lower than model group at various time point, the expression of ephedrine + high-dose naloxone group minimum, the difference was significant;Conclusion: ephedrine and ephedrine + naloxone treatment groups can effectively speed up the cerebral ischemic injury in rats recovery of motor function, nerve regeneration and synaptic reconstruction of speed, and with increasing doses of naloxone and its role more Obviously in promoting rehabilitation, ephedrine + high-dose naloxone treatment group have strongest role, a separate application of naloxone treatment group compared with the model group no significant role in promoting. Its mechanism may be associated with high-dose naloxone (0.3mg/kg/d) in cerebral ischemia was significantly inhibited by early and continued to maintain the low expression ofβ-EP, reduced apoptosis in ischemic hippocampus, reducing ischemic partial brain edema, to improve blood flow and thus with ephedrine positive role in rehabilitation and the creation of synergies to accelerate neural remodeling, and other mechanisms have to be further explored. |
PDF Full Text Request