The Efficacy of Recombinant Platelet-Derived Growth Factor on Beta-Tricalcium Phosphate to Regenerate Femoral Critical Sized Segmental Defects: Longitudinal In Vivo Micro-CT Study in a Rat Model

Abstract

Background and Objectives: Beta-tricalcium phosphate (beta-TCP) has been used for bone regeneration. The objective of this study was to assess longitudinally, the regeneration of critical sized segmental defects (CSSD) in rat femur using beta-TCP with or without recombinant platelet-derived growth factor (PDGF) through in vivo micro-computed tomography (micro-CT). Materials and Methods: Following ethical approval unilateral femoral CSSD measuring 5 mm was surgically created, under general anesthesia, in 30 male Wistar-Albino rats (aged 12–18 months; weighing 450–500 g). CSSD was stabilized using titanium mini-plate (4 holes, 1.0 mm thick with 8 mm bar). Depending upon biomaterial used for regeneration, the animals were randomly divided into: Control group (N = 10): CSSD covered with resorbable collagen membrane (RCM) only; Beta-TCP group (N = 10): CSSD filled with beta-TCP and covered by RCM; Beta-TCP + PDGF group (N = 10): CSSD filled with beta-TCP soaked in recombinant PDGF and covered by RCM. Longitudinal in vivo micro-CT analysis of the CSSD was done postoperatively at baseline, 2nd, 4th, 6th, and 8th weeks to assess volume and mineral density of newly formed bone (NFB) and beta-TCP. Results: Significant increase in NFB volume (NFBV) and mineral density (NFBMD) were observed from baseline to 8-weeks in all groups. Based on longitudinal in vivo micro-CT at 8-weeks, beta-TCP + PDGF group had significantly higher (p < 0.01) NFBV (38.98 ± 7.36 mm³) and NFBMD (3.72 ± 0.32 g/mm³) than the beta-TCP (NFBV—31.15 ± 6.68 mm³; NFBMD—2.28 ± 0.86g/mm³) and control (NFBV: 5.60 ± 1.06 mm³; NFBMD: 0.27 ± 0.02 g/mm³) groups. Significantly, higher reduction in beta-TCP volume (TCPV) and mineral density (TCPMD) were 1 observed in the beta-TCP + PDGF group when compared to the beta-TCP group. Conclusion: Addition of recombinant PDGF to beta-TCP enhanced bone regeneration within rat femoral CSSD and increased resorption rates of beta-TCP particles.

Keywords:

• bone regeneration
• critical size segmental defect
• beta-tricalcium phosphate
• micro-computed tomography
• platelet-derived growth factor
• rat femur in vivo model

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Acknowledgments

The authors acknowledge the ‘‘Deanship of Scientific Research’’ and ‘‘College of Dentistry Research Center’’ (Registration no. PR 0043), King Saud University, Riyadh, Saudi Arabia for their help and support.

Declaration of interest

The authors report no conflicts of interest.

Ethical approval

Ethical committee at the College of Dentistry Research Center, King Saud University, Riyadh, Saudi Arabia. (CDRC approval #PR 0043)