Bone morphogenetic protein 3b expressing reindeer antler^†

A cDNA sequence of bone morphogenetic protein 3b (BMP-3b) of reindeer antler was produced with degenerative homology primers in polymerase chain reaction (PCR). An in situ hybridization study of BMP-3b mRNA in 1-month-old antler showed expression in most differentiated cells in the antler center. In addition, the bone-inductive capacity of the reindeer antler matrix was evaluated. Decalcified and powdered antler matrix of different stages of antler maturity was implanted in gelatin capsules under the rat dorsal muscle fascia for two implantation periods: 3 and 8 weeks. Allogenic matrix prepared from rat long bones was used as a positive control implant. Heterotopic ossification was evaluated histomorphometrically and densitometrically. Allogenic bone matrix induced rapid osteogenesis and mineral accumulation. Both endochondral and intramembranous ossification was evident, endochondral ossification being the dominant form. Mineral density in the induced ossicle was 115 ± 48 mg/cm³ as early as at 3 weeks and 350 ± 69 mg/cm³ at 8 weeks. The proportional areas of von Kossa-stained mineral were 3.67 ± 2.1% and 11.6 ± 0.07%, respectively. The antler preparations induced mineralization, but significantly less than the allogenic bone matrix. At 8 weeks, mineral density was significantly lower in the cast antler preparation than in the allogenic implants. The morphology of the mineralized areas of the antler preparations showed no ossification. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 78–83, 2002