[Effects of astragalus polysaccharides-chitosan/polylactic acid scaffolds and bone marrow stem cells on repairing supra-alveolar periodontal defects in dogs].

Objective: To explore the effect of astragalus polysaccharides-chitosan/polylactic acid (AP-C/PLA) scaffolds and bone marrow stem cells (BMSCs) on periodontal regeneration of experimentally horizontal periodontal defects in dogs.

Methods: Dog BMSCs were isolated from the bone marrow and then cultured in a conditioned medium to be induced for osteogenesis. The expressions of Type I collagen and alkaline phosphatase (ALP) were examined by immunohistochemistry and histochemistry in the induced BMSCs, respectively. The BMSCs were harvested and implanted with astragalus polysaccharides-chitosan/polylactic acid (AP-C/PLA) and chitosan/polylactic acid (C/PLA) scaffolds. Horizontal alveolar bone defects (5 mm depth, 2 mm width) were produced surgically in the buccal side of the mandibular premolar 3 and 4 of the 10 dogs. The defects were randomly repaired with a cell-scaffold construction (10 teeth per group): root planning only (surgical control), AP-C/PLA with a conditioned medium (medium control), C/PLA with BMSCs (scaffolds control), and AP-C/PLA with BMSCs (experimental group) . The dogs were killed at 4 weeks and 8 weeks after the surgery, and block sections of the defects were collected for the histologic and histometric analysis.

Results: BMSCs induced in vitro exhibited an osteogenic phenotype with expressing Type I collagen and ALP histologically. The bone nodule structure was observed in the experimental group 4 weeks postsurgically. The engineered bone became more mature,similar to the native bone 8 weeks postsurgically. The amount of new bone regeneration and the rate of new bone filling to the defect height of the experimental group were significantly different from those of the surgical control, medium control, and scaffolds control [(2.90+/-0.41) mm vs (0.83+/-0.30) mm, (1.46+/-0.55) mm, (2.67+/-0.26) mm; 57.46% vs 15.68 %, 30.13%, 51.87%)] (P<0.01, P<0.01, P<0.05).

Conclusion: Astragalus polysaccharides can promote the new bone formation on the periodontal defects. The technology of tissue engineering with AP-C/PLA scaffolds and induced BMSCs may contribute to the periodontal regeneration.