Changes In GFAP Expression Of Astrocytes In Brain And Spinal Cord Following A Sharp-knife-cut Trauma To The Facial Region Of Rats

[Abstract]To investigate the expression patterns of glial fibrillary acidic protein(GFAP)of astrocyts in the brain and the spinal cord after a sharp-knife-cut trauma to the facial region.Methods:To set up a facial injury model of nociceptive pain,a sharp surgical knife blade was used to cut the skin and masseter on the left face of rats.A total of 25 healthy adult SD rats were randomly divided into the following groups:control,sham gand experimental. Then the experiment group was subdivided into three groups by the survival time after the trauma:1h,3h and 6h with each group consisting of 5 rats.The rats of each group were perfused with 4%Paraformaldehyde at 1h,3h,6h after operation,respectively.The brain and the cervical segments of spinal cord were removed for cryosectioning.Immunohistochemisty were used to examine the expression of GFAP and the quantitative and morphological changes of astrocytes,the adjacent section were undergone Nissl staining to discriminate the locations of nucleus.Result The immunoreactivities of GFAP in all the Sp5,VP,S1,CA1,CA2,CA3,DG and the dorsal horn of cervical cord of each experimental group were significantly enhanced compared with the control group and the sham group,respectively(p＜0.05).The lh group was the most obvious,while it reduced in 3h group,in 6h group decreased markedly.The expression of GFAP in all examined nucleus of brain were distinctive in sham group and control group(p＜0.05),but there were no differences in cervical cord (p＞0.05).Conclusion The injury of the face can activate the astrocyte to express GFAP in the trigeminal nerves pathway,the limbic system and the cervical cord.Our data suggests that astrocytes may play a very important role in modulation of nociceptive information.