J Neuroinflammation. 2005 Nov 18;2:26.
Cytokine responses during chronic denervation.
Ruohonen S, Khademi M, Jagodic M, Taskinen HS, Olsson T, Röyttä M.

Department of Pathology, University of Turku, Kiinanmyllynkatu 10, 20520 Turku, Finland. saku.ruohonen@utu.fi
BACKGROUND: The aim of the present study was to examine inflammatory responses during Wallerian degeneration in rat peripheral nerve when the regrowth of axons was prevented by suturing. METHODS: Transected rat sciatic nerve was sutured and ligated to prevent reinnervation. The samples were collected from the left sciatic nerve distally and proximally from the point of transection. The endoneurium was separated from the surrounding epi- and perineurium to examine the expression of cytokines in both of these compartments. Macrophage invasion into endoneurium was investigated and Schwann cell proliferation was followed as well as the expression of cytokines IL-1beta, IL-10, IFN-gamma and TNF-alpha mRNA. The samples were collected from 1 day up to 5 weeks after the primary operation. RESULTS: At days 1 to 3 after injury in the epi-/perineurium of the proximal and distal stump, a marked expression of the pro-inflammatory cytokines TNF-alpha and IL-1beta and of the anti-inflammatory cytokine IL-10 was observed. Concurrently, numerous macrophages started to gather into the epineurium of both proximal and distal stumps. At day 7 the number of macrophages decreased in the perineurium and increased markedly in the endoneurium of both stumps. At this time point marked expression of TNF-alpha and IFN-gamma mRNA was observed in the endo- and epi-/perineurium of the proximal stump. At day 14 a marked increase in the expression of IL-1beta could be noted in the proximal stump epi-/perineurium and in the distal stump endoneurium. At that time point many macrophages were observed in the longitudinally sectioned epineurium of the proximal 2 area as well as in the cross-section slides from the distal stump. At day 35 TNF-alpha, IL-1beta and IL-10 mRNA appeared abundantly in the proximal epi-/perineurium together with macrophages. CONCLUSION: The present studies show that even during chronic denervation there is a cyclic expression pattern for the studied cytokines. Contrary to the previous findings on reinnervating nerves the studied cytokines show increased expression up to 35 days. The high expressions of pro-inflammatory and anti-inflammatory cytokines in the proximal epi-/perineurial area at day 35 may be involved in the formation of fibrosis due to irreversible nerve injury and thus may have relevance to the formation of traumatic neuroma.

Matsumoto Y, Kawabe M, Yasue T, Yuguchi M, Yoshida I.

Case 1, a 49-year-old male who had been engaged in repair and reclamation of automobile tires, developed symptoms of vibration syndrome (Raynaud’s phenomenon, numbness of both hands, tinnitus and impaired hearing) after some 30 years’ use of a grinder and impact wrench. Two years thereafter, multiple sclerodermic lesions appeared over the trunk, upper extremities, and thighs; these disappeared about 2 years later. Histologically, hyperplasia and nodular swelling of collagen bundles were present in the dermis. An immunological study showed the serum to be positive for anti-centromere antibody, but no visceral lesions were demonstrable. This case corresponded to generalized morphea. Case 2, a 53-year-old male, developed symptoms of vibration syndrome (Raynaud’s phenomenon, numbness of both hands, impaired hearing and arthralgia) after 25 years’ use of a jack hammer in a quarry. Thereafter, sclerodermic changes of the forearms, lower legs, face and abdomen occurred with an associated sclerodactyly. Histological examination of involved skin revealed diffuse hyperplasia and homogenization of collagen bundles throughout the entire thickness of the dermis. These findings, together with serum positivity for anti-RNP antibody and dilation of the lower portion of the esophagus, led us to a diagnosis of progressive systemic sclerosis. We inferred that the vibration syndrome in the present cases might be related etiologically to these forms of scleroderma.

PMID: 2545958 [PubMed - indexed for MEDLINE]

H. Megel 1, H. Wozniak 1, L. Sun 1, E. Frazier 1, and H. C. Mason 1
1 Bioastronautics Section, Aero-Space Division, The Boeing Company, Seattle, Washington

Restrained adult male rats of the Sprague-Dawley strain were exposed for a 20-min duration to sublethal intensities of heat, vibration, and to the combination of heat and vibration. The incidence of mortality resulting from simultaneous exposure to both environmental stresses was significantly greater than would be predicted if these stresses were to act independently of each other. Hematocrit, hemoglobin, and serum glutamic-oxalacetic transaminase levels were significantly elevated immediately after vibration. Heat in combination with vibration increased these values although heat stress per se caused no change from control levels. Twenty-four hours after exposure to the combination of vibration and heat, hematocrit and hemoglobin levels returned to normal but the serum glutamic-oxalacetic transaminase levels were still significantly elevated. Significant increases in heart, kidney, and adrenal weights were observed immediately after exposure to the combination of environmental stresses. Possible modes of action are discusse