Transplantation of NSPCs expressing mutant forms of Rho GTPases. (A) Number of surviving cells in sections of spinal cords 7 days after transplantation. After transplantation of CA forms of cdc42 and rhoA, numbers of the surviving cells were significantly lower than the control cells expressing only lacZ (LacZ-positive control; 620.0 ± 90.9 cells, CdcCA; 235.6 ± 38.5 cells (p < 0.05), RacCA; 317.3 ± 60.5 cells, RhoCA; 0.0 cells (ANOVA, p < 0.01)). Although expression of the DN form of cdc42 reduced the number of surviving cells, expression of the DN form of rac1 increased the number of surviving cells (GFP-positive control; 723.3 ± 117.6 cells, CdcDN; 232.8 ± 88.8 cells (p < 0.01), RacDN; 1013.6 ± 39.7 cells (ANOVA, p < 0.05), RhoDN; 760.8 ± 162.9 cells). Double infection of adenoviruses expressing RacDN and RhoDN further enhanced the survival of transplanted NSPCs (1258.5 ± 133.6 cells (ANOVA, p < 0.01 in comparison with two types of control conditions)). (B) Increase in the total number of surviving NSPCs by expression of DN forms of both Rac and Rho. Complete serial sections of the transplanted spinal cords were examined and the total numbers of GFP-positive cells in two conditions were counted. A significant increase in surviving cells was observed in the condition of infecting two DN forms of Rho GTPases (control; 2565.2 ± 583.9 cells, RhoDN and RacDN; 6439 ± 990.6 cells, t-test p < 0.01). (C) Number of surviving cells in sections of spinal cords three weeks after transplantation. Double infection of adenoviruses expressing RacDN and RhoDN enhanced the survival of transplanted NSPCs (RacDN and RhoDN; 791.6 ± 156.9 cells, GFP-positive control; 320.8 ± 80.4 cells, t-test p < 0.05).