The aims of this study, using a porcine model of multiple trauma, were to investigate the expression of microRNAs at the fracture site, in the fracture haematoma (fxH) and in the fractured bone, compared with a remote unfractured long bone, to characterize the patterns of expression of circulating microRNAs in plasma, and identify and validate messenger RNA (mRNA) targets of the microRNAs. Two multiple trauma treatment strategies were compared: early total care (ETC) and damage control orthopaedics (DCO). For this study, fxH, fractured bone, unfractured control bone, plasma, lung, and liver samples were harvested. MicroRNAs were analyzed using quantitative real-time polymerase chain reaction arrays, and the identified mRNA targets were validated in vivo in the bone, fxH, lung, and liver tissue.Aims
Methods
MicroRNAs (miRNAs ) are small non-coding RNAs
that regulate gene expression. We hypothesised that the functions
of certain miRNAs and changes to their patterns of expression may
be crucial in the pathogenesis of nonunion. Healing fractures and
atrophic nonunions produced by periosteal cauterisation were created
in the femora of 94 rats, with 1:1 group allocation. At post-fracture
days three, seven, ten, 14, 21 and 28, miRNAs were extracted from
the newly generated tissue at the fracture site. Microarray and
real-time polymerase chain reaction (PCR) analyses of day 14 samples
revealed that five miRNAs, miR-31a-3p, miR-31a-5p, miR-146a-5p,
miR-146b-5p and miR-223-3p, were highly upregulated in nonunion.
Real-time PCR analysis further revealed that, in nonunion, the expression
levels of all five of these miRNAs peaked on day 14 and declined
thereafter. Our results suggest that miR-31a-3p, miR-31a-5p, miR-146a-5p,
miR-146b-5p and miR-223-3p may play an important role in the development
of nonunion. These findings add to the understanding of the molecular mechanism
for nonunion formation and may lead to the development of novel
therapeutic strategies for its treatment. Cite this article:
