Absence of genotoxic effects after exposure of mammalian cells to the recombinant human bone morphogenetic protein 2 (BMP-2) prepared from E. coli

Recombinant human bone morphogenetic protein 2 (rhBMP-2) has been widely employed for the induction of bone growth in animal models and in clinical trials. Since rhBMP-2 is commercially available only to a very limited extent, we have prepared our own recombinant material for the current testing and for future applications. As yet, no toxicological data on rhBMP-2 has been reported to the knowledge of the authors. Therefore, it was considered necessary to apply the in vifro-micronucleus assay to our preparation to monitor a possible genotoxic effect. A total of approximately 24500 nuclei from V79 Chinese hamster cells and more than 40000 nuclei from human amniotic fluid fibroblast-like (AFFL) cells were screened for the frequency of micronuclei following incubation with 3-300 nM rhBMP-2, which covers the concentration range from initial biological activity to the begin of a maximal response in MC3T3-E1 cells. It can be concluded from the results that our preparations of recombinant human BMP-2 prepared in E. coli do not cause DNA damage in the concentration range tested.