| Objective: Hypoxic-ischemic brain damage(HIBD) could result in neonatalmorbidity and mortality, some patients with HIBD developed into cerebral palsy and mental retardation. So far no specific neuroprotective intervention after hypoxia-ischemia (H-I) has been available. Recently, the experimental studies indicated that electroacupuncture(EA) could improve the brain blood circulation, attenuate the neurotoxicity of nitric oxide(NO) and the incidence of sequela in asphyxial neonatal rats with cerebral palsy; EA could extenuate cellular edema and mitochondrial swelling in ischemic rats. These results demonstrated that EA had the capacity to promote the recovery of brain damage. A great deal of studies were to treat the acute cerebral ischemia on adult rats with EA, however, there were fewer reports about the treatment and the long-term effects of EA on HIBD in neonatal rats. The present study was done to observe the influence of electroacupuncturing "BaiHui" and "DaZhui" points on the expression of ChAT and BDNF, the ultrastructural changes, Nissl body changes in hippocampus and cerebral cortex in neonatal rats as the model of cerebral H-I; so as to confirm the effects of EA on HIBD , investigate the possible mechanism, and provide the theoretical basis for clinical application.Methods: 61 healthy 7-d-old Wistar rats weighing 12-15g were randomly dividedinto three groups . Group I , Sham-operated control group(n=16): the normal rats only received the operation without H-I treatment. Group II, H-I group(n=23, only 19 rats up to the standard): the rats were subjected to permanent ligation of left side artery and exposured to hypoxia(8% oxygen in nitrogen) for 2 hours. Group III, H-I + EA group(n=21, only 19 up to the standard): from the second day after H-I, the rats were electroacupunctured on "Bai Hui" and "DaZhui" points synchronously, the needle handles were respectively connected to stimulative machine( 16Hz, 10V), the rats received 10 min treatment each day, each course contained 10 treatments, 2 d interval between two courses. 24h after hypoxia , three rats in group I and group II respectively were random put to death for TTC(2,3,5-Triphenyltetrazolium bromide) staining. 22 d Later, three rats were selected from each group and killed . The left side hippocampus from each rat was dissected out, the specimens were fixed in 4% glutaraldehyde solution, then routinely dehydrated, and embedded into epoxy resin 618#, ultrathin sections were prepared and stained by uranyl acetate and lead citrate, an electron microscope H-7500 was used for observation. The 42 rats left were subjected to perfiision-fixation 22 d later, the brains were regularly paraffin wax embedded, sectioned and stained by HE staining, Nissl staining, ChAT and BDNF immunohistochemical staining. The neuron structures were observed, the number of positive neurons counted under microscope and the grey scale values were measured, the data were statistically analysed with SPSS 10.0.Results:1. HE staining: the structure of neurons was clear in group I ; however, in group II, there were marked tissue swelling , neuronal degeneration and necrosis , the cellular structure was clouding, the nuclear chromatin distribution was not homogeneous; group III revealed decreased tissue swelling , neuronal degeneration and necrosis, the cellular structure was almost normal.2. ChAT immunohistochemical staining: ChAT positive neurons distributed widely in CA1, CA2, CA3 and dentate gyms subfields of group I (CA1: 29.74+4.85); the number of them declined markedly in the CA1 subfield of group II(13. 96+7.62),and as compared with group I , there was significant difference( p<0.05); increased markedly in group 111(25.54± 5.05), as compared with group II(p<0.05). There was no significant difference between group III and group I.3. BDNF immunohistochemical staining: BDNF positive neurons were less in the cortex and CA2 and CA3 subfields of group I(cerebral cortex: 14.14±6.11 , hippocampus: 13.42... |
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