Objective: To evaluate the effects of composite bone in strategy of tissue engineering on bone defect repair in rats.
Methods: Sixteen matured Wistar rats (male or female, weighing 250-300 g) were used to prepare platelet lysate (PL). PL/allogeneic decalcified bone granules (ADBG)/Col I (PAC) and ADBG/Col I (AC) were prepared by mixing Col I gel ADBG with or without PL. BMSCs of 8 Wistar rats (male or female, weighing 250-300 g) were isolated and cultured. The 5th passage of BMSCs were co-cultured with PAC at the density of 1 x 10(6) cells/mL to fabricate the tissue engineered composite PACB in vitro. Forty healthy Wistar rats were made bilateral bone defects in femoral condyles and divided into 4 groups (A, B, C and D, n=10). The defects were filled with equivalent PACB, PAC, AC and Col I in groups A, B, C and D respectively. At 4 weeks, the defect repair was evaluated with radiology, histology, ALP biochemical tests.
Results: At 4 weeks, the bone density measurement was (7.31 +/- 0.54), (4.36 +/- 0.67), (2.12 +/- 0.47), and (1.09 +/- 0.55) pixels in groups A, B, C, and D, respectively. The area of new bone formation in defect area under single view was (412.82 +/- 22.31), (266.57 +/- 17.22), (94.34 +/- 20.22), and (26.12 +/- 12.51) pixels in groups A, B, C and D respectively. The ALP contents in femoral condyles were (94.31 +/- 7.54), (69.88 +/- 4.12), (41.33 +/- 3.46), and (21.03 +/- 3.11) U/L, respectively. The above indexes of group A were significantly higher than those of groups B, C or D (P < 0.05). Three-color flow cytometry assay showed that the T lymphocyte subsets of CD3(+)CD4(+)CD8(-), CD3(+)CD8(+)CD4(-), and the ratio of CD4/CD8 displayed no significant difference among four groups (P > 0.05).
Conclusion: Tissue engineered bone PACB is capable to promote the bone defect repair.