Immunohistochemical Study on the Effects of the Sciatic Nerve Transection on the Astroglial Cells of the Spinal Cord in Rats

Park, Ye Soo; Cho, Jae Lim; Hwang, Se Jin; Chung, Ho Sam

Abstract

GFAP(glial fibrillary acidic protein), a major compositional protein of intermediate filaments of astrocytes, is known to be increased in the process of reactive astrocytosis following various neurotoxic injury. Fibronectin, an extracellular glycoprotein, is known to be absent in normal glial cells in matured animals, but it can be re-expressed after the insult of the nervous system. To investigate tile neuronal and glial changes resulting from neurotoxicity induced by sciatic nerve resection, morphological and immunohistochemical studies were made in the rat spinal cord following sciatic nerve transection. The results obtained were as follows: 1. Nuclear pyknosis, chromatolysis of the neuronal cells and increased microglial cells were observed in dorsal horns. And motor neurons of ventral horns were observed in the ipsilateral spinal cord after sciatic nerve transection . 2. Immunoreactivity of GFAP in dorsal and ventral horns was increased in ipsilateral spinal cord from 1 day to 4 weeks after sciatic nerve transection which showed maximal activity 1 week after transection. 3. Fibronectin immunoreactivity in ipsilateral spinal cord began to increase 1 week and reached maximal activity 4 weeks after sciatic nerve transection. It is consequently suggested that sciatic nerve transection induces the neuronal damages in dorsal and ventral horns. In addition, increased GFAP immunoreactivity is resulted from the activation of the astrocytes following neuronal degeneration, while increased fibronectin immunoreactivity may reflect the healing process of the peripheral nerve fibers.