Effect Research Of Different Frequencies Electro-Acupuncture On Brain Astrocytes In Rats With Focal Cerebral Ischemia

Objective To investigate the effect of different electroacupuncture (EA) frequency stimulus on astroglia of focal cerebral ischemic rats, to seek the proper electroacupuncture frequency and the mechanism of electroacupuncture treatment on ischemia rats.Methods Thirty-six male SD rats were randomly divided into 4 groups: control group,15Hz group,30Hz group,100Hz group,9 rats in each group. Middle cerebral artery occlusion (MCAO) was induced cerebral infarction on the rats by the thread embolism method. The neurological deficit scores were evaluated on the rats after electroacupuncture treatment with different frequency.The ultrastructural of astroaytes,the positive astroaytes cells and optial densitity of border of infarct focus (area A),the ipsilateral parietal lobe area(area B) and the cortex of contralateral corresponding with focus(area C) were detected by immunohistochemical methods of glial fibrillary acid protein(GFAP) and electron microscope.Results Compared with the control group, the neurological deficit scores of rats in 15Hz group and 30Hz group were lower (P<0.05), but it did not show any difference in 100Hz group(p>0.05). Immunohistochemical staining showed the positive astroaytes cells extensively increased in area A and area B compared with control group(p<0.05),but it did not showed any difference in area C for each group(p>0.05);the opital densitity of aastroaytes was same so. Electron microscopy showed:In area A of these groups, Control group, hypertrophy of astrocytes,increased organelle and its cell cytoplasm, the nuclear cytoplasm ratio was decreased; sparse structure of nerve tissue and myelin structure of layered performance;severe degeneration of neurons; synaptic structural abnormalities.15Hz group of astrocytes was less cytoplasm, large proportion of nuclear plasma, rich in heterochromatin and organelles increased;nerve tissue was compacted structure, the structural integrity of myelin and abundant organelle; mild degeneration of neurons; synaptic structure was normal.In area A of 30Hz group and 15Hz group was similar under the electron microscope.100Hz group of astrocytes, its cytoplasm increased, its nuclear cytoplasm ratio decreased, rich in heterochromatin and the characteristics of its organelles increased;the compacted structure of nerve tissue,edema can be seen with some neurite; moderate degeneration of neurons; synaptic structure and control groups were similar.In area B,C of these groups, ultrastructural changes of astrocytes with normal astrocytes as, its neurons and its structure was normal.Conclusion Different electroacupuncture doses can influence reactive activity of astroaytes after cerebral ischemic rats in its area A,area B,area C, and with the best frequencies for 15hz and 30hz,there may be neuroprotective effect.The expression change of GFAP that electroacupuncture induces may be one of the endogenous cerebral protection mechanism that electroacupuncture induces cerebral ischemia tolerance.Acupuncture produces ischemic tolerance which is one of the mechanisms,which may be by perserving the integrity of astrocytes.