[Research on marrow mesenchymal stem cell proliferation by coculturing with Schwann cell]

To evaluate the effect of Schwann cell (SC) on the proliferation of marrow mesenchymal stem cells (MSCs) and provide evidence for application of SC in construction of the tissue engineered vessels.

SC and MSCs were harvested from SD rats (weight 40 g). SC were verified immunohistochemically by the S-100 staining, and MSCs were verified by CD 44, CD 105, CD 34 and CD 45. The 3rd passages of both the cells were cocultured in the Transwell system and were amounted by the 3H-TDR integration technique at 1, 3, 5 and 7 days, respectively. The results were expressed by the CPM(counts per minute, CPM) values. However, MSCs on both the layers were served as the controls. The Western blot was performed to assess the expression of the vascular endothelial growth factor (VEGF), its receptor Flk-1, and the associated receptor neuropilin 1 (NRP-1) in SC, the trial cells, and the controls.

SC had a spindle shape in the flasks, and more than 90% of SC had a positive reaction for the S-100 staining. MSCs expressed CD44 and CD105, and had a negative signal in CD 34 and CD 45. The CPM values of MSCs in the trial groups were 2,411.00+/-270.84, 3,016.17+/-241.57, 6,570.83+/-2,848.27 and 6,375.8+/-1,431.28 at 1, 3, 5 and 7 days, respectively. They were significantly higher in their values than the control group (2,142.17+/- 531.63, 2,603.33+/-389.64, 2,707.50+/-328.55, 2,389.00+/-908.01), especially at 5 days (P<0.05). The Western blot indicated that VEGF was expressed obviously in both the SC group and the cocultured MSCs group and was less visible in the control cells. The expressions of Flk-1 and NRP-1 in the cocultured MSCs were much stronger than in the controls.

SC can significantly promote the proliferation of MSCs when they are cocultured. The peak time of the proliferation effect appeared at 5 days. This effect may be triggered by the up-regulation of VEGF in MSCs, which also leads to the upregulation of Flk-1 and NRP-1.