Leukocyte-platelet-rich plasma diminishes bone matrix deposition in rat calvaria treated with autograft due to simultaneous increase in immunohistochemical expression of Indian Hedgehog, transforming growth factor-ß, and parathyroid-1 receptor.

PURPOSE: This study evaluated the immunohistochemical presence of Indian Hedgehog (IHH), transforming growth factor-ß (TGF-ß), and parathyroid-1 receptor (PTH1R) in calvaria bone repair, and compared these results with the histological bone matrix features in defects treated with autograft in the presence or absence of L-PRP. MATERIAL AND METHODS: An artificial bone defect measuring 5 × 1 mm was produced in the calvaria of 28 Wistar rats. Randomly the defects were treated with autograft and autograft mixed with L-PRP. The animals were euthanized at 15 and 40 days post-surgery. Data were analyzed by Student-Newman-Keuls test (p ≤ .05) for immunohistochemical interpretation. RESULTS: The results revealed that the histological characteristic of bone matrix deposited in the defect was different in the defects treated with L-PRP. The group that received only the autograft demonstrated larger haversian bone matrix deposited, whereas the group that received autograft mixed with L-PRP revealed trabecular bone deposition. These results coincided with significantly higher immunopositivity for IHH, TGF-ß1, and PTH1R in the L-PRP group. CONCLUSION: These results suggest that L-PRP altered the biological characteristic of the autograft, increasing the bone cells IHH+ but inducing a trabecular bone associated with intense quantities of TGF-ß and PTH1R.

Leukocyte-platelet-rich plasma (L-PRP) impairs the osteoconductive capacity of the autograft associated to changes in the immunolocalization of TGF-ß1 and its co-expression with Wnt10b and CD34 cells.

BACKGROUND: This study evaluated the osteoconductive effect of an autograft, in the presence or absence of the L-PRP, using histomorphometric analysis of the bone formed, and we compared the results in the presence of TGF-ß1, Wnt10b and CD34 detected by immunohistochemistry. MATERIALS AND METHODS: Two bone defects were produced in the calvaria of 20 rabbits. The defects were treated with autograft and autograft combined with L-PRP. The animals were euthanized at 15 and 40 days post-surgery. Data were analyzed by Student-Newman-Keuls (p ≤ 0.05) test for histomorphometric and immunohistochemical interpretation. RESULTS: The results revealed that the presence of bone matrix was significantly less in the defects treated with L-PRP. These results coincided with changes of the immunolocalization of the TGF-ß1. In the L-PRP-free groups the TGF-ß1 was restricted to bone matrix while the CD34 was scarce and the Wnt10b occurred in peritrabecular cells. In contrast, in defects that received L-PRP the presence of TGF-ß1 occurred in cells, which occupied whole area of defect. These TGF-ß1+ cells also were co-expressed to Wnt10b and CD34. CONCLUSION: These results suggest that L-PRP induces a cross-reaction between TGF-ß1 and Wnt10b, which stimulates the self-renewal and maintenance of CD34+ stem cells immunophenotype, impairing the osteoconductivity properties of the autograft.