The axonal regeneration of neurons in the motor cortex of adult hamsters

Abstract

A segment of autologous sciatic nerve was transplanted into the motor cortex which was verified by retrograde labelling.Eight weeks after the implantation the presence of regenerated motor neurons was visualized by HRP histochemistry following the injection of the tracer into the distal end of the sciatic nerve graft. Labelled pyramidal neurons were found in the motor cortex suggesting that these neurons had sent their axons into the graft(n=12. mean=9.75). Implantation of the preconditional treatment of sciatic nerves which had been crushed a week prior to transplantation did not enhance the regeneration of pyramidal neurons in the motor cortex (n=9, mean=7.56). Furthermore. implantation of the sciatic nerve which was subjected to freezeand-thaw treatment was unable to induce regeneration of neurons in the cortex. the present study suggests that the peripheral nerve graft can induce regeneration of motor neurons in the cortex in hamsters and that the axonal regeneration of the CNS neurons may be related to the activity of the Schwann cells present in the peripheral nerve graft.

在用ＨＲＰ逆行追蹤法確定金黃地鼠大腦運動皮質的準確位置后，將截取的三組實驗動物的自體坐骨神經分別插入之。存活８周后，在坐骨神經移植段的遠端，注射２０％ＨＲＰ溶被１μｌ，做全腦及脊髓頸段連續冰凍切片，觀察ＨＲＰ逆行標記的運動皮質錐體細胞。結果發現：在移植的正常坐骨神經段的誘導下，運動皮質神經元的受損軸突可以再生并長入到該移植段內（ｎ＝１２，平均＝９．７５），用預先漬變法未能導致運動皮質軸突再生神經元數目的增加（ｎ＝９，平均＝７．５），而經凍化處理后的移植神經則未能誘導出運動皮質神經元的軸奕再生。本文結果證明，周圍神經移植法可誘導成年金黃地鼠運動皮質神經元的軸突再生，雪旺氏細胞的存在及其功能活動與錐體神經元軸突再生密切相關。