Ischemic reperfusion causes lipid peroxidation and fiber degeneration

Neurotoxicity of isolated limb perfusion with tumor necrosis factor

Hyperthermic isolated limb perfusion (HILP) with tumor necrosis factor alpha (TNFalpha) is effective for advanced melanoma and sarcoma of the limbs. Ten patients undergoing HILP with TNFalpha were evaluated by neurological examinations, nerve conduction studies (NCS), sympathetic skin responses (SSR) and conventional and quantitative electromyography (EMG), performed before, 7 days and 6 weeks following HILP. Seven patients showed minimal clinical signs of peripheral nerve damage following HILP; in two the injury was evident electrophysiologically: 7 days following HILP five patients had paresthesias and/or hypoesthesia, one had a mild foot drop and one had autonomic disturbances in the affected limb. SSR was low in two patients in the affected limb, sensory nerve action potentials were not elicited in one, with normal motor NCS and EMG. At 6 weeks, four patients continued to have mild paresthesias and one had dysautonomia of the perfused limb. Sensory responses and SSR did not change, motor abnormalities were not found. These findings show that HILP with TNFalpha induces a mild, mainly sensory neuropathy in perfused limbs, not disturbing functionality and improving over time.

Carbonyl histochemistry in rat reperfusion nerve injury

Free radical mediated, site-specific lipid and protein oxidation has been implicated in the pathophysiology of an ischaemic/reperfusion injury. The aim of the present study was to determine whether carbonyl formation could be detected histochemically in reperfused rat sciatic nerves. We also examined the effects of preischaemic alpha-tocopherol supplementation on carbonyl formation in reperfused nerves. Seven hours of near-complete ischaemia was induced in rat right hindlimb by occlusion of major arteries using microvascular clips. Histochemical detection of carbonyl compounds, applying naphthoic acid hydrazide (NAH) and Fast Blue B (FBB), was undertaken at thigh, knee and calf levels of sciatic, tibial and peroneal nerves. NAH-FBB reactivity was confined to vessels in reperfused nerves. Positively stained epi-, peri- and endoneurial vessels were invariably observed after 2 h of reperfusion at all levels examined. After 24 and 48 h and 7 days of reperfusion, NAH-FBB-positive vessels were more frequently found at knee and calf levels than at the thigh level. Following preischaemic alpha-tocopherol supplementation, no vessels were stained positively with NAH-FBB, except for some epineurial vessels at knee and calf levels after 2 h of reperfusion. Morphometry in endoneurial vessels at the knee level revealed that endothelial cell area in alpha-tocopherol-treated reperfused nerves was significantly less when compared with those in reperfused nerves without alpha-tocopherol. In conclusion, we have demonstrated histochemical evidence of carbonyl formation in vessels, but not with nerve fibres, in ischaemic/reperfused rat sciatic nerves. These abnormalities were prevented with preischaemic supplementation of alpha-tocopherol.