Abstract
The techniquein situ hybridization was used to measure the levels of light (NF-L), medium (NF-M) and heavy (NF-H) neurofilament protein subunits mRNA in L4-6 spinal motoneurons in adult rat during regeneration following a unilateral crush of the sciatic nerve. It was found that the hybridization signals of each neurofilament subunit rnRNA were dramatically decreased in spinal motoneurons postaxotomy by light microscopy. The hybridization signals of NF-L and NF-M mRNA were located in cytoplasm of neurons, whereas NF-H mRNA was found in both nucleus and cytoplasm of neurons. Image analysis showed that the encoding levels of mRNA for each of neurofilament subunit mRNA reduced on the 3rd d and returned to control levels on the 28th d following the lesion. The relative levels of mRNA coding for each neurofilament subunit were significantly different. The lowest level of NF-L mRNA was observed at 5 d postaxotomy, and that of NF-M, NF-H mRNA on the 7th and 10th d after injury. Moreover, the levels of HF-M and NF-H mRNA were reduced much lower and lasted much longer than that of NF-L mRNA. The observations suggest that there were different mechanisms for the regulation of neurofilament subunit genes expression. The reduced neurofilament gene expression may be due to a response to axonal injury and advance the restructure of axonal architecture.
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References
Gan, S. D., Fan, M., He, G. P., The role of microtubule in axoplasmic transportin vivo, Brain Res., 1986, 396: 75.
Mullins, F. H., Hargreaves, A. J., Li, J. Y.,et al., Tyrosination state of α-tubulin in regenerating peripheral nerve,J. Neurochem., 1994, 62: 227.
Flienger, K. H., Liem, R. K. H., Cellular and molecular biology of neuronal intermediate filaments,Int. Rev. Cytol., 1991, 131: 109.
Hoffman, P. H., Thompson, C. W., Griffin J. W.et al., Changes in neurofilament transport coincide temporally with alterations in the caliber of axons in regenerating motor fibers,J. Cell Biol., 1985, 101: 1332.
He, B., Fan, M., Gan, S. D., Expression of α tubulin gene in spinal motoneurons during nerve regeneration,Chin. Sci. Bull., 1993, 38(5): 432.
Mi, R. F., Gan, S. D., Fan, M., Changes of β, γ actin gene expression in spinal motoneurons during nerve regeneration,Chin. Sci. Bull., 1994, 39(6): 542.
Fan, M., Gan, S. D., Changes of microtubulin, neurofilament and axonal cross section during nerve regeneration,Chin. J. Appl. Physiol., 1993, 9: 129.
Clark, E. A., Lee, W. Y., The differential role of protein kinase C isozymes in the rapid induction of neurofilament phosphorylation by nerve growth factor and phorbol esters in PC12 cells,J. Neurochem., 1991, 57: 802.
Schlaepfer, W. W., Zimmerman, U. J. P., Calcium-mediated breakdown of glial filaments and neurofilaments in rat optic nerve and spinal cord,Neurochem. Res., 1981, 6: 243.
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Mi, R., Shi, X., Liu, S. et al. Expression of neurofilament gene in spinal motoneurons during neural regeneration. Chin.Sci.Bull. 44, 225–229 (1999). https://doi.org/10.1007/BF02896279
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DOI: https://doi.org/10.1007/BF02896279