Unravelling the secrets of foetal wound healing: an insight into fracture repair in the mouse foetus and perspectives for clinical application.

This study was designed to investigate the nature of mammalian foetal fracture healing in utero. A compound 'pinch' fracture was created in the foetal mouse ulna at the end of the second trimester, prior to mineralisation, and healing observed in whole mount limbs and in histological section. Cartilaginous ends gained initial contact within a perichondrial sleeve by 24 h. Bony union was achieved within 48 h by cartilage remodelling during the phase of primary endochondral ossification in the limb, a process to which adult fracture healing aspires. The molecular response to wounding was investigated using a whole mount in situ hybridisation technique and antisense mRNA probes to three target genes (BMP-2, BMP-4 and GDF-5). These experiments failed to identify altered expression in wounded limbs compared with controls.