Experimental study on tissue engineering platelet lysates in the promotion of bone reconstruction

Abstract

To evaluate the effects of tissue engineered allogeneic platelet lysates (PL) upon bone reconstruction. After preparation of recombinant material with PL, allogeneic decalcified bone granules (ADBG) and collagen type I (CG), 30 healthy Wistar rats were used to prepare the bilateral bone defects in femoral condyles. The defects were filled with equivalent PL/ADBG/CG, ADBG/CG and CG in different groups of A, B and C (with 10 rats each) respectively. At 4 weeks, the defect reconstruction was evaluated with radiology, histology, immunology and biomechanics. (1) The X-ray showed that bone density in group A (4.18 +/- 0.96) was close to that of normal bone and it was significantly higher than that in group B (2.36 +/- 0.87) and group C (1.09 +/- 0.55) (P < 0.01). (2) In comparisons with B and C, the histological assay revealed that there were markedly more activities of new bone formation and more implanted bone granules surviving without significant lymphocyte infiltration, as well as more osteoclastic bone resorption in group A. The bone histomorphometric assay showed the newly formed bone area in group A (286.73 +/- 17.22) was significantly higher than that in group B (94.34 +/- 33.56) and group C (19.12 +/- 14.53) (P < 0.01). (3) Anti-press mechanical measures showed that the destructive load in A, B, C and normal control group was 259.63 +/- 34.57, 187.90 +/- 21.07, 91.33 +/- 26.58 and 311.93 +/- 82.45 respectively. The destructive energy in A, B, C and normal control group was 10.82 +/- 1.44, 7.83 +/- 0.88, 3.81 +/- 1.11 and 12.97 +/- 3.43 respectively. These results showed either destructive load or destructive energy in group A was markedly higher than that in group B and group C with significant difference (P < 0.01), but still lower than that in normal controls (P < 0.01). (4) Three-color flow cytometry assay showed that the T lymphocyte subsets of CD3+CD4+CD8-, CD3+CD8+CD4- and the ratio of CD4/CD8 showed no significance difference within these three groups as well as normal controls. Tissue engineering PL (PL/ADBG/CG) is capable of accelerating the regenerative repair of bone defect and promoting the bone regeneration and osetointergretion of allograft bone after transplantation.