Regenerative Medicine for Battlefield Injuries
Abstract
The purpose of this research is to identify the optimum combination of growth factors that stimulate cartilage regeneraton across a critical size defect (CSD) in a long bone, using the axolotl, Abystoma mexicanum as a model system. The scope of the research is to characterize fracture repair and determine the length of the CSD in the fibula, use bioinformatics analysis and biochemical analysis of limb proteins to reveal the potential growth factors involved in CSD regeneration, and test these growth factors for their ability to stimulate cartilage regeneration when delivered by a standard pig small intestinal submucosa scaffold (SIS). In year one, we have characterized the response of the fibula to fracture and segment defects of 10, 20, 40 and 50% via X-ray, CT, methylene blue/alizarin red (MB/AR) limn skeleton whole mount staining, and H& E staining of sections at intervals of 15 days, one month, six weeks, two months and three months post-operation. Cartilage formation is detected by H& E staining within one month after fracture and by six weeks with MB stain. The cartilage is mature by 3 months and can be visualized by X-ray and CT. Using the same imaging methods, we determined that the CSD (length at which 50% or more of cases fail to regenerate) is slightly less than 40% of the length of the bone. Because 50% defects fail to regenerate by 3 months in 100% of cases, we will use these defects to test growth factors. We found that a gelatin-coated 8-strand SIS braid releases protein continually for at least 72 hr., indicating that the choice of this scaffold was the right one. Experiments grafting axolotl cartilage and muscle to Xenopus tarsal CSDs indicate that the tissues enhance regeneration, most probably by a paracrine effect; they also enhance regeneration of amputated Xenopus limbs, providing evidence that limb proteins are capable of stimulating regeneration across gaps.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 2012
- Accession Number
- ADA611583
Entities
People
- David L. Stocum