Experimental Study of Changes of beta-catenin, PCNA, Substance P after Peripheral Nerve Compression in Rat

Yang, Young Churl; Lee, Seung Jae; Hong, Kwan Hee

Abstract

The ultrastructural changes of sciatic nerve and immunohistochemical changes of beta-catenin, PCNA, substance P were studied at the proximal segment of rat sciatic nerve after compression injury. We used 90 Sprague Dawley rats and the sciatic nerve compressed using silicon tube. We divided experimental groups which were the compression group for 1 hour (1C), for 2 hours (2C), and for 3 hours (3C), the release group for 1 day (1C1R) and 3 days (1C3R) after the compression for 1 hour, the release group for 1 day (2C1R) and 3 days (2C3R) after the compression for 2 hours, the release group for 1 day (3C1R) and 3 days (3C3R) after the compression for 3 hours. The rats were sacrified and took the sciatic nerve specimen. The specimens were investigated under the light microscope after hematoxylin & eosin, toluidin blue, and immunohistochemical stainings. In the H & E finding, the axon of the 1C disappeared, but recovered at the 1C3R. The part of nerve fibers at the 2C were swollen, but began to be partially recovered at 2C3R. Most nerve fibers were enlarged at the 3C, but markedly decreased at the 3C1R. The beta-catenin reaction disappeared at the 1C, but almost recovered at the 1C3R. This reaction of the 2C disappeared in the large fibers, but began to be recovered in the small fibers at the 2C1R. This reaction of the 3C disappeared in the large fibers, but began to be recovered at the 3C1R and 3C3R. The PCNA reaction prominently appeared at the 1C3R and 2C3R, the more prominent reaction at the 3C1R, and markedly increased reaction at the 3C3R. The substance P reaction of the 1C1R was mild positive, and the 2C1R and 3C1R were strong positive. In the toluidin blue staining, the myelin sheaths near the perineurium began to be thickened at the 1C, but almost recovered at the 1C3R. Many myelin sheaths became to be very thickened at the 2C and 3C, but almost recovered at the 2C3R and 3C3R. In the electron microscopic findings, the myelin sheaths of the 1C underwent the demyelination with the separated lamellae and the increase microtubules. At the 1C3R, the axolemma was attached on the myelin sheath and the axon was recovered. the myelin sheaths of the 2C underwent the demyelination with the separated axolemma. At the 2C1R, the myelin sheath was recovered by the developing Schwann cells, many intraaxonal mitochondria of demyelinated nerve fibers. At the 2C3R, the myelin sheath tended to be recovered by the increased rough endoplasmic reticulum and mitochondria of Schwann cells, many intraaxonal mitochondria of demyelinated nerve fibers. The myelin sheaths of the 3C began to be underwent severe demyelination from the middle portion of the sheath and the vacuolization of intraaxonal mitochondria. At the 3C1R, the myelin sheaths were recovered and contained many extended microtubules, mitochondria, and small granules. At the 3C3R, severe demyelinated nerve fibers were recovered by increasing microtubules. The proximal retrograde degeneration of sciatic nerve by the acute compression appeared the loss of the axons and the swelling of nerve fibers. The beta-catenin reaction was disappeared by the compression, but recovered by releasing. This reaction may be played a important role of the recover of demyelination. The PCNA reaction of Schwann cells was increased by the nerve compression. In the substance P finding, the pain after the compression appeared at the 1 day after releasing. Electron microscopic changes after sciatic nerve compression were the demyelination, the separated lamellae and the increase of intraaxonal microtubules. After releasing, the nerve fibers were recovered by developing Schwann cell, the intraaxonal mitochondria, and the transported granules through extending microtubules.