Interleukin-1 activity in lesioned peripheral nerve.
The cytokine interleukin-1 (IL-1) is involved in a wide range of inflammatory and immune responses. As such, IL-1 could play a role in peripheral nerve repair mechanisms. Specifically, by its already established properties as a regulator of nerve growth factor (NGF) synthesis, and as a chemotactant to macrophages. We examined, therefore, IL-1 production in injured mouse peripheral nerve. Injured nerve segments were incubated in serum free medium to produce conditioned medium (CM) that was then tested for IL-1 activity in a thymocyte proliferation assay. CM induced thymocyte proliferation in a dose-dependent manner. Proliferation was inhibited by the M20 IL-1 inhibitor, the IL-1 receptor antagonist, and antisera raised against recombinant mouse IL-1 alpha. Inhibitions produced by these three specific inhibitors of IL-1-induced thymocyte proliferation strongly suggest that proliferation induced by CM was mediated largely by IL-1 secreted by non-neuronal cells residing in the damaged nerve. IL-1 activity was detected within hours after lesion, and 1 week thereafter. The rapid and prolonged production of IL-1 indicates that IL-1-dependent mechanisms can play roles in the response of the peripheral nerve to injury: degeneration and regeneration. The regulation of NGF synthesis, and the recruitment of white blood cells, macrophages in particular, from blood into the damaged nerve tissue, are two such mechanisms.
Rotshenker
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S
Department of Anatomy, Hadassah hospital Medical School, Jerusalem, Israel.
Aamar
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S
Barak
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V
D000818:Animals; D001369:Axons / Q000648:ultrastructure; D002455:Cell Division / Q000187:drug effects; D003470:Culture Media; D003714:Denervation; D007375:Interleukin-1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D009416:Nerve Regeneration / Q000502:physiology*; D012584:Sciatic Nerve / Q000378:metabolism* / Q000502:physiology; D013950:Thymus Gland / Q000166:cytology; D013997:Time Factors; D014855:Wallerian Degeneration
D003470:Culture Media; D007375:Interleukin-1