Platelet-leukocyte-rich plasma (L-PRP) prevents the collagen III degradation and impairs the bone matrix development in artificial defect of rabbit calvaria, associated with suppression of the immunohistochemical expression of MMP-2 and MMP-9

Resumo

Because L-PRP constitutes an important
source of growth factor that is associated with osteogenesis and
fibrogenesis, the aim of this study was to evaluate the effect of
L-PRP on the presence of collagen III and MMP-2 and MMP-9, while
comparing these results by means of a histomorphometric analysis
of bone matrix and fibrous deposition on bone repair. Material
and methods: Four bone defects of 8 × 2 mm were created on
the calvaria of 21 rabbits. The surgical defects were treated with
either particulate autograft, particulate autograft mixed with L-PRP,
or L-PRP alone. Animals were euthanized at 2, 4, and 6 weeks
postoperative. Histomorphometric and immunohistochemical analyses
were performed to assess repair time, as well as the expression of collagen III and MMPs. Results: In contrast to the results of the
L-PRP-free groups, the histomorphometric results of the L-PRP groups
demonstrated intense fibrotic deposition along with hindered bone
matrix deposition. These results coincided with the larger occurrence
of diffuse collagen III deposition and the scarce presence of MMP2 and -9 spread among the fibrous tissue. Conclusion: Thus, the
results suggest that L-PRP not only induces an intense fibrosis rich
in collagen III, which is not degraded, but also suppresses MMP-2
and -9 expressions, mimicking a similar pathological event as that
of a cleft-palate or cranial suture.