Scherer S S, Kamholz J, Jakowlew S B
Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia 19104.
Glia. 1993 Aug;8(4):265-76. doi: 10.1002/glia.440080407.
We have investigated the expression of transforming growth factor (TGF)-beta 1,-beta 2, and -beta 3 in developing, degenerating, and regenerating rat peripheral nerve by immunohistochemistry and Northern blot analysis. In normal adult sciatic nerve, TGF-beta 1, -beta 2, and -beta 3 are detected in the cytoplasm of Schwann cells, and the levels of TGF-beta 1 and -beta 3 mRNAs are constant during post-natal development. When sciatic nerves are transected to cause axonal degeneration and prevent axonal regeneration, the level of TGF-beta 1 mRNA in the distal nerve-stump increases markedly and remains elevated, whereas the level of TGF-beta 3 mRNA falls modestly and remains depressed. When sciatic nerves are crushed to cause axonal degeneration and allow axonal regeneration, the level of TGF-beta 1 mRNA initially increases as axons degenerate, and then falls as axons regenerate. TGF-beta 2 mRNA was not detected in developing or lesioned sciatic nerves at any time. Cultured Schwann cells have high levels of TGF-beta 1 mRNA, the amount of which is reduced by forskolin, which mimics the effect of axonal contact. These data demonstrate that Schwann cells express TGF-beta 1, -beta 2, and -beta 3, and that TGF-beta 1 and -beta 3 mRNA predominate over TGF-beta 2 mRNA in peripheral nerve. Axonal contact and forskolin decrease the expression of TGF-beta 1 in Schwann cells.
我们通过免疫组织化学和Northern印迹分析，研究了转化生长因子（TGF）-β1、-β2和-β3在发育、退变和再生的大鼠周围神经中的表达情况。在正常成年坐骨神经中，雪旺细胞的细胞质中可检测到TGF-β1、-β2和-β3，且TGF-β1和-β3 mRNA的水平在出生后发育过程中保持恒定。当切断坐骨神经导致轴突退变并阻止轴突再生时，远端神经残端中TGF-β1 mRNA的水平显著升高并持续升高，而TGF-β3 mRNA的水平则适度下降并持续降低。当挤压坐骨神经导致轴突退变并允许轴突再生时，TGF-β1 mRNA的水平最初随着轴突退变而升高，然后随着轴突再生而下降。在发育中的或损伤的坐骨神经中，任何时候都未检测到TGF-β2 mRNA。培养的雪旺细胞具有高水平的TGF-β1 mRNA，其含量可被福司可林降低，福司可林可模拟轴突接触的作用。这些数据表明，雪旺细胞表达TGF-β1、-β2和-β3，且在周围神经中TGF-β1和-β3 mRNA比TGF-β2 mRNA占优势。轴突接触和福司可林可降低雪旺细胞中TGF-β1的表达。
