Immunoexpression of BMP-2 protein on bone repair of critical size defects treated with autogenous macerated adipose tissue

Resumo

The adipose tissue is an important reservoir of adult
stem cells which have capacity of differentiating in osteoblasts
with potential implication in reaching bone regeneration. The
evaluation of the osteoblastic differentiation can be verified through
immunohistochemical markers such as bone morphogenetic protein2 (BMP-2). Objective: To evaluate the immunoexpression of BMP-2
protein on the bone repairing of critical size defects (CSD) surgically
created in rat calvaria and treated by autogenous macerated adipose
tissue. Material and methods: Forty male rats had a CSD measuring
5 mm created on their calvaria. The animals were randomly divided
into two groups: group C (control) and group AT (macerated adipose
tissue grafting). In group C, the defect was filled with only blood
clot. In group AT, the defect was filled with autogenous macerated
adipose tissue. The groups were subdivided into two subgroups
(n = 10) for euthanasia at 7 and 90 post-operative days. Histological and
immunohistochemical analyses were carried out. Data were submitted
to descriptive statistics (mode). Results: In group AT, both at 7 and 90 post-operative days, the main healing type was the presence of dense
conjunctive tissue exhibiting bundles of collagen fibers disposed in
beams permeating the remaining adipose tissue with rare heterotopic
bone formation associated to fibrosis and different types of tissue
necrosis. In group C, the repair was achieved by the formation of
bundles of collagen fibers oriented parallelly to the surface of the wound
at the two post-surgical periods. The immune-staining of BMP-2 was
present only in group C (7 and 90 post-operative days). Conclusion:
Within the limits of this present study, it can be concluded that the
adipose tissue grafting did not favor bone neoformation in critical size
defects and BMP-2 signaling was not observed.