Tissue-engineered peripheral nerve grafting by differentiated bone marrow stromal cells

Bone marrow stromal cells are multipotential stem cells that contribute to the differentiation of tissues such as bone, cartilage, fat and muscle. In the experiment, we found that bone marrow stromal cells can be induced to differentiate into cells expressing characteristic markers of Schwann cells, such as S-100 and glial fibrillary acidic protein, promoting peripheral nerve regeneration. Tissue-engineered bioartificial nerve grafting of rats by differentiated bone marrow stromal cells was applied for bridging a 10 mm-long sciatic nerve defect. Twenty-eight inbred strains of female F344 rats weighing 160∼200 g were randomly divided into four nerve grafting groups, with seven rats in each group. Differentiated bone marrow stromal cell–laden group: poly(lactic-co-glycolic) acid tubes with an intrinsic framework were seeded with syngeneic bone marrow stromal cells which were induced for 5 days; Schwann cell–laden group: poly(lactic-co-glycolic) acid tubes with an intrinsic framework were seeded with syngeneic Schwann cells; acellular group: poly(lactic-co-glycolic) acid tubes were only filled with an intrinsic framework; autografts group. Three months later, a series of examinations was performed, including electrophysiological methods, walking track analysis, immunohistological staining of nerves, immunostaining of S-100 and neurofilament, and axon counts. The outcome indicated that bone marrow stromal cells are able to differentiate into Schwann-like cells and Schwann-like cells could promote nerve regeneration. Bone marrow stromal cells may be potentially optional seed cells for peripheral nerve tissue engineering because of abilities of promoting axonal regeneration.