RESUMO
BACKGROUND: The objective of this study was to thoroughly examine the in vivo angiogenesis activity of human recombinant tumor necrosis factor alpha (rhTNF). METHODS: rhTNF (0.5 ng to 1.0 microgram) was incorporated into the slow release polymers Hydron or HYPAN and implanted into the rabbit cornea. Release of biologically active rhTNF from the polymers was determined with the L929 cytotoxicity assay. RESULTS: All concentrations tested failed to elicit capillary formation beyond that observed for controls. Less than 2% of the rhTNF was released from the Hydron over 7 days. HYPAN released five times the amount of rhTNF in vitro, but even at doses of 500 ng (104.3 ng suggested release) no angiogenesis was stimulated. CONCLUSIONS: Under the circumstances tested, rhTNF is not angiogenic in vivo.