The optimal carrier for BMP-2: a comparison of collagen versus fibrin matrix.

Introduction: The aim of our study was to investigate in vitro and in a new in vivo rat model for impaired bone healing whether a low dose BMP-2 preparation in fibrin would be equivalent or better than the combination of collagen and a high dose of BMP-2 which is currently in clinical use.

Materials And Methods: In a 14 day period we compared the in vitro release kinetics of an absorbable collagen sponge (ACS) with 72 μg rhBMP-2 in the BMPC group and fibrin matrix with 10 μg rhBMP-2 in the BMPF group. In our in vivo experiment a critical sized osteotomy was performed in the rat femur, which was filled with a spacer, inhibiting bone formation for a period of 4 weeks.

Skeletal muscles, heart, and lung are the main sources of oxygen radicals in old rats.

The aim of this study was to compare rat tissues with respect to their reactive oxygen and nitrogen species (RONS) generating activities as a function of age. We quantified the RONS generation in vivo in young (6 months) and in old (30 months) male Sprague-Dawley rats using the recently developed spin trap 1-hydroxy-3-carboxy-pyrrolidine, applied intravenously. This spin trap reacts with superoxide radical and peroxynitrite yielding a stable spin adduct which is detectable by means of electron paramagnetic resonance (EPR) spectroscopy in frozen tissues.

Epr analysis reveals three tissues responding to endotoxin by increased formation of reactive oxygen and nitrogen species.

The excessive formation of reactive oxygen and nitrogen species (RONS) in tissue has been implicated in the development of various diseases. In this study we adopted ex vivo low temperature EPR spectroscopy combined with spin trapping technique to measure local RONS levels in frozen tissue samples. CP-H (1-hydroxy-3-carboxy-pyrrolidine), a new nontoxic spin probe, was used to analyze RONS in vivo.