Long-term anticalcification effect of Fe3+ in rat subdermal implants of glutaraldehyde preserved bovine pericardium

Fe3+ preincubation has been shown to inhibit pathologic calcification of glutaraldehyde preserved bovine pericardium (GPBP) in the short-term rat subdermal model (21 days). This study was designed to test the long-term anticalcification efficacy of Fe3+ in the same model. Glutaraldehyde preserved bovine pericardium was preincubated (1 hr, 25 degrees C) in 0.1M FeCl3, 0.01M FeCl3, or 0.05M HEPES, then implanted subdermally in weanling male rats (40-60 gm) for 21, 60, 90, and 120 days. At explant, Fe3+ and Ca2+ levels were measured by atomic absorption spectroscopy. Fe3+ effectively inhibited calcification in both experimental groups compared to control through the longest implant (Ca2+ levels, 120 day implant: 0.1M FeCl3 = 46.85 +/- 17.45 micrograms/mg; 0.01M FeCl3 = 17.31 +/- 7.38 micrograms/mg; control = 258.04 +/- 15.71). Measurement of explanted GPBP Fe3+ levels showed that tissue Fe3+ levels of at least 7.28 +/- 0.70 micrograms/mg were required to effectively inhibit calcification after a 120-day implant. There was no evidence of Fe3+ impairment of rat growth. In conclusion, Fe3+ pretreatment of GPBP significantly inhibited calcification after long-term (120 day) rat subdermal implant.