CARBONYL HISTOCHEMISTRY IN RAT REPERFUSION NERVE INJURY

Free radical mediated, site-specific lipid and protein oxidation has b een implicated in the pathophysiology of an ischaemic/reperfusion inju ry. The aim of the present study was to determine whether carbonyl for mation could be detected histochemically in reperfused rat sciatic ner ves. We also examined the effects of preischaemic alpha-tocopherol sup plementation on carbonyl formation in reperfused nerves, Seven hours o f near-complete ischaemia was induced in rat right hindlimb by occlusi on of major arteries using microvascular clips. Histochemical detectio n of carbonyl compounds, applying naphthoic acid hydrazide (NAH) and F ast Blue B(FBB), was undertaken at thigh, knee and calf levels of scia tic, tibial and peroneal nerves. NAH-FBB reactivity was confined to ve ssels in reperfused nerves, Positively stained epi-, peri- and endoneu rial vessels were invariably observed after 2 h of reperfusion at all levels examined. After 24 and 48 h and 7 days of reperfusion, NAK-FBB- positive vessels were more frequently found at knee and calf levels th an at the thigh level. Following preischaemic alpha-tocopherol supplem entation, no vessels were stained positively with NAH-FBB, except for some epineurial vessels at knee and calf levels after 2 h of reperfusi on. Morphometry in endoneurial vessels at the knee level revealed that endothelial cell area in alpha-tocopherol-treated reperfused nerves w as significantly less when compared with those in reperfused nerves wi thout alpha-tocopherol. In conclusion, we have demonstrated histochemi cal evidence of carbonyl formation in vessels, but not with nerve fibr es, in ischaemic/reperfused rat sciatic nerves. These abnormalities we re prevented with preischaemic supplementation of alpha-tocopherol. (C ) 1997 Elsevier Science B.V.