STUDY DESIGN.: In vivo rodent model. OBJECTIVE.: Investigate the effect of systemic corticosteroid administration on soft-tissue inflammation after local delivery of recombinant human bone morphogenetic protein-2 (rhBMP-2). SUMMARY OF BACKGROUND DATA.: Corticosteroid use in cases of soft-tissue inflammation associated with the use of rhBMP-2 has been reported in clinical studies, but the effectiveness of its use and appropriate timing remain unclear. METHODS.: Absorbable collagen sponges were implanted with control or rhBMP-2 into the lumbar region of rats subcutaneously and intramuscularly. Four groups were studied: group I, control sponge only; group 2, BMP-2 sponge only; group III, BMP-2 sponge and preoperative intraperitoneal methylprednisolone (MPSS); group IV, BMP-2 sponge with MPSS given on day 2. Using magnetic resonance imaging, inflammation was assessed in terms of soft tissue edema volume at 0, 2, 4, and 7 days. Rats were sacrificed after 7 days for gross and histological analysis. RESULTS.: The peak mean intramuscular inflammatory volume occurred on day 2 in all groups. Group II (BMP-2 without MPSS) had a significantly higher peak mean inflammatory volume (405.46 mm) on day 2 than that of groups I (266 mm), III (278 mm), and IV (291 mm) (P = 0.001). No significant difference in intramuscular soft-tissue inflammation was observed between the control group and the groups receiving MPSS on day 0 or day 2 at any time point. No differences in the area of inflammatory cell infiltrate surrounding the sponge was observed histologically, after sacrificing them, in groups treated with BMP-2. CONCLUSION.: Systemic MPSS administration reduced soft tissue edema associated with rhBMP-2 as measured by magnetic resonance imaging, but no effect was observed on the histological area of inflammation. Further studies are required to elucidate if there is any benefit to the use of corticosteroid administration in reducing the area of inflammation associated with the use of rhBMP-2.
- infl ammation
ASJC Scopus subject areas
- Orthopedics and Sports Medicine
- Clinical Neurology